3 boys and 5 girls can finish a project in 6 days, while 2 boys and 7 girls can finish it in 8 days. In how many days will 8 girls complete it?

Correct option is C

Given:

3 boys and 5 girls can finish a project in 6 days, while 2 boys and 7 girls can finish it in 8 days.

​Formula Used:​

M1 × D1 = M2 × D2

​Solution:​

3 boys and 5 girls can finish a project in 6 days, while 2 boys and 7 girls can finish it in 8 days => (3B + 5G) × 6 = (2B + 7G) × 8

 18B + 30G = 16B + 56G

 2B = 26G

​$$\frac{B}{G} = \frac{13}{1}$$​​

Now let 8 girls complete the project in D days,

then  (3B + 5G) × 6 = 8G × D

 (3 × 13 + 5 × 1) × 6 = 8 × 1 × D

 44 × 6 = 8 × D

 D = 33 days

In 33 days 8 girls complete the work.