Explanation:
since the ratio of children to adult is 2:7,
2+7 = 9
number of children would be
(2 × 2700)/9 = 600 children in the crowd
number of adults would be
(7 × 2700)/9 = 2100 adults in the crowd
So, if a ticket costs £8 per adults, total cash made from adult
= 8 × 2100 = £16800
if a ticket costs £(8 - 3) per children, total cash made from children
= 5 × 600 = £3000
total money made = £(16800 + 3000)
= £19800