Question

Three boxes are labelled A, B and C and each box contains four balls numbered 1, 2, 3 and 4. The balls in each box are

well mixed. A child chooses one ball at random from each of

the three boxes. If a, b and c are the numbers on the balls chosen from the boxes A, B and C resepctively, the child wins a toy helicopter when a = b + c. The odds in favour of the child to receive the toy helicopter are-

• A. 3 : 32
• B. 3 : 29
• C. 1 : 15
• D. 5 : 59

Answer 1

Answer: (B)

3 : 29

Answer 2

Here, n(S) = 4 × 4 × 4 = 64 and n(1) = 211 or 312

or 413

or 431 or 422

\ P(5) = $\frac { 6 } { 64 }$ = $\frac { 3 } { 32 }$ = $\frac { 3 } { 3 + 29 }$

Odds in favour 3 : 29