(a) Amount shared = D(M - 15)
Sister's share = \(\frac{D(M - 15)}{2}\)
\(\implies \frac{D(M - 15)}{2} = \frac{1}{3}M\)
\(2M = 3(M - 15) \implies 3M - 2M = 45\)
\(M = 45.00\)
(b) (i)
(ii) (1) Total no interviewed = \(\frac{2}{5}x + \frac{4}{15}x + \frac{1}{6}x + 20 = x\)
\(\therefore 12x + 8x + 5x + 600 = 30x\) (Multiplying through with their LCM which is 30)
\(600 = 30x - 12x - 8x - 5x = 5x \implies 600 = 5x\)
\(x = \frac{600}{5} = 120\)
(2) Those that travelled by air only = \((\frac{13}{30} \times 120) - (\frac{4}{15} \times 120)\)
= \(52 - 32 = 20\)
