Ai Tong School P5 SA1 2006 Math (Q45)

At Ai Tong Restaurant, the charge for the buffet lunch per person is $15. For every group of 10 people, the 11th person does not have to pay.

(a) What will be the total charge for a party of 23 people?
(b) How many people are there in the group if the bill comes up to $720?


Solution

10 people ----- 10 x $15 = $150
11th person ----- free
1 group of 11 ----- $150

(a) What will be the total charge for a party of 23 people?

23 people ----- 2 groups of 11 people + 1 individual
2 groups of 11 ----- 2 x $150 = $300
1 individual ----- $15
Total ----- $300 + $15 = $315

Answer: The charge for a party of 23 people is $315.


(b) How many people are there in the group if the bill comes up to $720?

For every $150 ----- 11 people
$720 ----- $600 + $120
$600 ----- $600 divided by $150 = 4 (groups of 11 people)
$120 ----- $120 divided by $15 = 8 individuals

Therefore, $720 ----- 4 groups of 11 people + 11 individuals
(4 x 11) + 8
= 44 + 8
= 52

Answer: There are 52 people if the bill comes up to $720.