## anonymous one year ago Please Help will give medal! Frankie can build a speaker box in 120 minutes. Tisha can build a speaker box 40 minutes faster. If they work together, how many minutes does it take them to build the speaker box?

1. anonymous

I think it's B

2. ♪Chibiterasu

There are no options but ok: x/120 +x/40 =1 x +3x =120 4x=120 x=30 minutes $\frac{ x }{ 120 } + \frac{ x }{ 40 } = 1$ x + 3x = 120 4x = 120 x = ?

3. anonymous

x = 30

4. ♪Chibiterasu

Yeah.

5. anonymous

It's not one of the choices, I'm confused.

6. anonymous

7. anonymous

@Hi-xx @hughfuve @pandaecat @bruno102 @gabbimanges17 @The_Yee_Dinosaur @ctwatson @ximevazq @dwoodruff

8. Hero

1. The amount of time it will take when they work together will be less than the time it takes Tisha to do it alone. 2. To find the time it takes for Frankie and Tisha to build the speaker together, let F = the time it takes Frankie to build the speaker alone T = the time it takes Tisha to build the speaker alone Then input those values into the following expression: $\dfrac{F \times T}{F + T}$ and then evaluate the expression.

9. anonymous

It's 30 but that's not the answer the choices are 40 minutes 48 minutes 80 minutes 240 minutes

10. Hero

If it were me, I'd pick the lowest amount. 40 could be a typo.

11. anonymous

Alright I'll try...

12. anonymous

It was wrong. :(

13. Hero

If that's wrong, then the other choices are more wrong.

14. Hero

30 is definitely the right amount of minutes.