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Question
primary 5 | Maths
| Rate & Ratio
2 Answers Below
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Not the usual ratio question
160-68 = 92
92÷2 = 46
(68-46)÷2 = 11
5×11 = 55 (Ans)
Algebra →
3u+p = 68
9u+3p = 3×68
5u+3p = 160
9u-5u=4u = 3×68-160 = 44
u = 11
5u = 55
See 2 Answers
⬛ represents 1 unit of adults
⬜ represents 1 unit of children
From the ratios, we can say that :
Children who left : ⬜⬜
Children remained : ⬜⬜⬜
Adults who left : ⬛⬛
Adults remained : ⬛
Based on the ratios and numbers,
⬛⬛⬜⬜ = 92 ①
⬛⬜⬜⬜ = 68 ②
Notice that these two models have everything the same except 1 ⬜ and 1⬛
So the difference between ⬛ and ⬜ = 92 - 68 = 24
So ⬛ is 24 more than ⬜
We can now rewrite ② as :
⬜ + 24 + ⬜⬜⬜ = 68
⬜⬜⬜⬜ = 68 - 24
⬜⬜⬜⬜ = 44
⬜ = 44 ÷ 4 = 11
Children who were at the park in the morning = ⬜⬜⬜⬜⬜ = 11 x 5 = 55