8 boys and 12 girls together can finish a project work in 5 days. If it takes 50 days for one boy alone to finish the same project, how many days are required for one girl alone to complete the same project work?

Correct option is C

Given:
8 boys and 12 girls can complete the project in 5 days.
1 boy alone can complete the project in 50 days. 

Formula Used: ​

Total work = Efficiency $$\times$$ Time​

Solution:

For Boys = B and Girls = G,

According to given information;

(8B + 12G) × 5 = 1B × 50

408 +60G = 50B

60G = 10B

​$$\frac{G}{B} = \frac{10}{60}$$

$$\frac{G}{B} = \frac{1}{6}$$ (Efficiency ratio)

Total work = (8 × 6 + 12 × 1) × 5

Total work = (48 + 12) × 5

Total work = 60 × 5

Total work = 300

Work done by 1 girl = $$\frac{300}{1}$$​​

Work done by 1 girl = 300 days

So,  300 days are required for one girl alone to complete the same project work.

Thus, the correct answer is (c).