A, B, C started a business with their investments in the ratio 1 : 3 : 5. After 4 months, A invested the same amount as before and B as well as C withdrew half of their investments. The ratio of their profits at the end of the year is :
(a)4 : 3 : 5
(b)5 : 6 : 10
(c)6 : 5 : 10
(d)10 : 5 : 6
Answer
Answer (as printed): B
Explanation
Let their initial investments be $x, 3 x$ and $5 x$ respectively. Then, $$\begin{aligned} A: B: C & =(x \times 4+2 x \times 8):\left(3 x \times 4+\frac{3 x}{2} \times 8\right):\left(5 x \times 4+\frac{5 x}{2} \times 8\right) \\ & =20 x: 24 x: 40 x=5: 6: 10 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.