This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Friday, April 25, 2008

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.

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