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P5 Mathematics

Question post on Mon, 02/05/2022 6:48pm

At a carnival, Mr. Lim purchased tokens for a class of 42 students. Each student was given the same number of tokens. 7 of the students gave up their tokens to the rest of the students. As a result, the rest of the students now received 3 more tokens each. How many tokens did Mr. Lim purchase at first?

Answer

ChiefKiasu · Answer 1 · Post on Mon, 02/05/2022 10:08pm

Thanks sushi88! Here’s how I would solve this by equations.

Let n be the number of tokens each student gets at first.

42 n = (42 – 7)(n + 3)
42 n = 35 n + 105
7 n = 105
n = 15

So Mr Lim bought 42*15 = 630 tokens at first.

sushi88 · Answer 2 · Post on Mon, 02/05/2022 10:32pm

Actually it’s fine as long as the student understands this method because PSLE accepts anything logical. Only in school, sometimes teachers have preference for method taught by them so that they know if the students are learning from them.

sushi88 · Answer 3 · Post on Mon, 02/05/2022 9:11pm

Total tokens purchase at first = u and it remains unchanged

Original—[u/42][u/42]———————————————–[u/42] students=42

New:——-[(u/42)+3][(u/42)+3]——————————-[(u/42)+3] students=42-7=35

Tokens given up for redistribution = 7 x (u/42) = u/6

Tokens given up and distributed to 35 students = 3 x 35 = 105

Hence, u/6 = 105 => u = 630