## shewolfangz 3 years ago a triangle and a rectangle are drawn on a page so that they overlap as shown. inside these figures are placed the digits from 0 to 9. if there are six digits in the triangle and eight digits in the rectangle, how many digits are in the part that belongs to both figures

1. shewolfangz

i dnt ge the working out

2. shewolfangz

get*

3. hartnn

six digits in the triangle-->Let T =6 eight digits in the rectangle---->Let R=8 Total = 10 digits. = T union R (in other words, T OR R) get this much ?

4. shewolfangz

how do u get 10 digits?

5. hartnn

0 to 9 means total 10 digits i assumed that the digits are not repeated, which is a fair assumption here...

6. shewolfangz

ohk...no they not repeated

7. hartnn

digits are in the part that belongs to "both" figures = T AND R (T intersection R) = ...... there is a formula for this, you know ? in terms of T,R and T UNION R

8. shewolfangz

but..how do u do year 7 working out..im suposed to draw the diagram and stuff..

9. hartnn

'year 7 working out.' ?? i didn't get you..

10. hartnn

|dw:1352896076101:dw|

11. shewolfangz

im in year 7

12. shewolfangz

|dw:1352896192555:dw|

13. shewolfangz

that's what the question look like

14. hartnn

|dw:1352896267033:dw| i am not sure i can give you exact working required by your course/teacher, but i can make u understand how to get the answer....

15. shewolfangz

ok..

16. hartnn

now look at that figure, if u want total area of composite figure, will it be appropiate to add the area of triangle and rectangle ?

17. shewolfangz

um...no?

18. hartnn

why ?

19. shewolfangz

i don't know

20. shewolfangz

by the area of composite figure do u mean the overlapped shape?

21. hartnn

yes,. because then you will consider the "intersection part" twice. once in rectangle and once in triangle, got this ?

22. shewolfangz

um..kinda

23. hartnn

so to get area of composite figure, u need to subtract are of intersection, right ?

24. shewolfangz

..uh..yea..

25. hartnn

so , we get TOTAL = RECT +TRIANGLE - INTERSECTION. in this case, total = 10 , Rect = 8, triangle =6 u just need intersection

26. shewolfangz

uhuh

27. hartnn

not clear ?

28. shewolfangz

clear

29. hartnn

so, 10 = 8+6-x where x is digits that belongs to both figures

30. hartnn

x= ?

31. shewolfangz

hmm equations..lets see

32. shewolfangz

4?

33. hartnn

yes, so there are 4 numbers that belong to both..

34. shewolfangz

ohk..

35. hartnn

will u be able to solve similar problems ?

36. shewolfangz

i think so yes

37. shewolfangz

thnx for ur help hartnn

38. shewolfangz

now i need to get back to my other hw

39. hartnn

welcome ^_^ and good luck....

40. shewolfangz

thnx for help!!!