Hi ,

Following pls find the worked solution:

N = 1u; T + M + C = 3u; Total = 4u --- (1)

T = 1u; N + M + C = 4u; Total = 5u --- (2)

M = 1u; N + T + C = 5u; Total = 6u --- (3)

Applying Unchanged Total concept ( total savings for M, N, T, C is the same for all 3 comparison statements above ), we need to find a common multiple for 4,5,6, which is 60.

Hence, total for each of the above comparisons = 60u.

So we have ...

(1) x 15: N = 15u; T + M + C = 45u; Total = 60u

(2) x 12: T = 12u; N + M + C = 48u; Total = 60u

(3) x 10: M = 10u; N + T + C = 50u; Total = 60u

C = 60u - N - T - M = 60u - 15u - 12u - 10u

= 23u

Given that C saves $1035, we have ...

23u --> 1035

1u --> 1035 / 23 = 45

Total savings of all 4 children = 60u --> 60 x 45 = $ 2700

================================================

Trust the above helps.

Cheers,

Edward