P5 maths question

Helengoo SG

Keith went shopping with thrice as many S$5 notes as S$2 notes . After he used 28 pieces of S$5 notes , he had 5 times as many S$2 notes as S$5 notes left . Find the total value of his remaining S$5 and S$2 notes .

Thanks

lolerchild SG

I would suggest using a model to better illustrate the problem.

But here's the algebra method

let original no. of $5 notes be x

let original no. of $2 notes be 1/3 x

5(x-28) = 1/3 x

15(x-28) = x

14x = 420

x = 30

value of remaining $5 notes = (30-28) * 5 = $10

value of remaining $2 notes = (30/3) * 2 = $20

Total value= $30

Helengoo SG

Hi Lolerchild ,

Thanks for your reply . However , I need the answer shown in model method . Need your assistance .

Regards .

lolerchild SG

as you can see,

in the beginning you have 3 times as many $5 as $2.

After using 28 notes of $5, you are left with 5 times as much $2 as $5.

Hence

14 blocks = 28 notes.

1 block = 2 notes

remaining $5 notes= 1*2 (2*$5=$10)

remaining $2 notes= 5*2 (10*2=$20)

total remaining=$30