sstrike's answer to Janice's Primary 5 Maths Whole Numbers Singapore question.
if u prefer the single child → u
instead of 2 kids → u , p
【kind of simultaneous equations solving in Sec】
wish this vertical model can help a bit
backwards【ratio way】
$10 ÷ 2 = $5
left
P : G = 2:1 = 2(u+5) : u+5
spent
P : G (D:B)= 1:2 = 2u : 4u
2(u+5) + u+5 + 2 + 4u = $285
u = $30
2u = $60 (Ans)
instead of 2 kids → u , p
【kind of simultaneous equations solving in Sec】
wish this vertical model can help a bit
backwards【ratio way】
$10 ÷ 2 = $5
left
P : G = 2:1 = 2(u+5) : u+5
spent
P : G (D:B)= 1:2 = 2u : 4u
2(u+5) + u+5 + 2 + 4u = $285
u = $30
2u = $60 (Ans)
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