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: Help..............In a school a certain number of boys and girls attend a certain examination. The mean mark of the boys was 40 and the mean mark of the girls was 60.Mean of all students is 48.Find the number of boys and girls in a class of 100.
 2 years ago
 2 years ago
: Help..............In a school a certain number of boys and girls attend a certain examination. The mean mark of the boys was 40 and the mean mark of the girls was 60.Mean of all students is 48.Find the number of boys and girls in a class of 100.
 2 years ago
 2 years ago

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wasiqssBest ResponseYou've already chosen the best response.0
(40x+60y)/100=48 x+y=100
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
solve two simoultaneous eq
 2 years ago

KingBest ResponseYou've already chosen the best response.0
not possible sorry wrong answer x+y needs to be 100
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
sorry i mean to say galx 40
 2 years ago

KingBest ResponseYou've already chosen the best response.0
oh ok but how did u get first two equations....xplain
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
listen what will be mean of marks? total marks divided by candidate
 2 years ago

KingBest ResponseYou've already chosen the best response.0
and what is x and what is y?
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
x is boys , y is number of galx
 2 years ago

KingBest ResponseYou've already chosen the best response.0
yeah but how 40 * x and 60 * y?
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
so the total marks is number of boys into their marks+number of galx nto their mean marks then divided by total number of students that s 100
 2 years ago

KingBest ResponseYou've already chosen the best response.0
why is 40 multiplied by x and 60 multiplied into y?
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
40 is the mean marks of boys and x is the total number of boys in class and y is total number of gals ad 60 is the mean marks of gal
 2 years ago

KingBest ResponseYou've already chosen the best response.0
yeah so why do we multiply?
 2 years ago

AnwarABest ResponseYou've already chosen the best response.0
OK. Let \(n\) and \(m\) be the number if boys and girls respectively, then \(40 n\) is the total points that boys scored, and \(60m\) is the total of the girls. We can then write \(\frac{40n+60m}{m+n}=48\). We also have \(m+n=100\). Solve them to find m and n.
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
we multiply to get the total number of marks like suppose there are 3 students in class and their mean mark is 90 so how we will get the marks obtained by class in total as in we want to add the marks of all the student
 2 years ago

AnwarABest ResponseYou've already chosen the best response.0
If you solve them, you will get \(n=70 \text{ boys, and } m=30 \text{ girls}\).
 2 years ago

KingBest ResponseYou've already chosen the best response.0
wasiq why will we multiply if 3 students are there then mmean is x1+x2+x3/3=90
 2 years ago

AnwarABest ResponseYou've already chosen the best response.0
Oh sorry, I solved them for \(46\), not \(48\). Wait a sec.
 2 years ago

KingBest ResponseYou've already chosen the best response.0
yea anwser is rite but i dont understand why we multiply...
 2 years ago

asnaseerBest ResponseYou've already chosen the best response.1
the mean of the these 3 numbers: 12,14,16 is calculated as:\[\frac{12+14+16}{3}=\frac{42}{3}=14\]the total of those 3 numbers is: 12+14+16=42, which is the same as the mean times the number of numbers you have: 14*3=42
 2 years ago

wasiqssBest ResponseYou've already chosen the best response.0
king u r dumb, sorry to say bt tru
 2 years ago

asnaseerBest ResponseYou've already chosen the best response.1
so, if you are given the mean and the number of items, you can always work out the total number of items as (mean)*(number of items)
 2 years ago

AnwarABest ResponseYou've already chosen the best response.0
Let me explain it to you. Assume we have 5 students, and their mean is 50. We can write that as \(\large{\frac{x_1+x_2+x_3+x_4+x_5}{5}=50}\). Now if we want to find the sum of the points that all the 5 student scored, we just multiply both sides by \(5\) to get \(\large {x_1+x_2+x_3+x_4+x_5=5\times 50}\). Makes sense?
 2 years ago

asnaseerBest ResponseYou've already chosen the best response.1
sorry "the total of all the items"
 2 years ago

KingBest ResponseYou've already chosen the best response.0
oh ok thnx anwar and asnaseer thnk u very much
 2 years ago

asnaseerBest ResponseYou've already chosen the best response.1
no problem  always glad to help
 2 years ago
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