Q&A - P5 Math

[alfretztay]

Can someone help me with this ratio problem. Thanks!

Hanson had some one-dollar coins and some fifty-cent coins. The ratio of the number of one-dollar coins to the number of fifty-cent coins he had was 2 : 5. Hanson took 140 fifty-cent coins to the bank and changed these fifty-cent coins for the same value of one-dollar coins. In the end, the number of one-dollar coins to the number of fifty-cent coins he had became 5 : 2. Find the value of the fifty-cent coins Hanson had at first.

one-dollar coins : fifty-cent coins
2u : 5u
+70 -140
5p : 2p

2u +70 -> 5p ... (1)
5u - 140 -> 2p ... (2)
(1) x 2 : 4u + 140 -> 10p ... (3)
(2) x 5 : 25u - 700 -> 10p ... (4)
(4) - (3) : 21u -> 840
1u -> 40
5u -> 200
200 x $0.50 = $100
Ans $100.

[Daddy]

Hi all,

I have questions to ask.



Thank alots..

[BigDevil]

There are equal number of muffins in the 4 trays as the 12 boxes.
Therefore, each tray has 3 times the number of muffins in one box.

Muffins in box -> u
Muffins in tray -> 3u

2 trays + 4 boxes -> 6u + 4u = 60
u = 6

Total muffins baked -> 4 trays + 12 boxes = 12u + 12u = 24u = 144 muffins

$432 / 144 = $3 each

===========================================

Work backwards.
In the end, Ali and May have $270 each after May gave Ali 1/4 of what she have.

$270 is 3/4 of what she had.
Before she gave Ali 1/4, she had ($270 / 3) x 4 = $360
Ali had $270 - $90 = $180

$180 is 4/5 of what Ali had.
Before Ali gave May 1/5, he had ($180 / 4) x 5 = $225

[pokemon]

Can someone help me with this ratio problem. Thanks!

Hanson had some one-dollar coins and some fifty-cent coins. The ratio of the number of one-dollar coins to the number of fifty-cent coins he had was 2 : 5. Hanson took 140 fifty-cent coins to the bank and changed these fifty-cent coins for the same value of one-dollar coins. In the end, the number of one-dollar coins to the number of fifty-cent coins he had became 5 : 2. Find the value of the fifty-cent coins Hanson had at first.

one-dollar coins : fifty-cent coins
2u : 5u
+70 -140
5p : 2p

2u +70 -> 5p ... (1)
5u - 140 -> 2p ... (2)
(1) x 2 : 4u + 140 -> 10p ... (3)
(2) x 5 : 25u - 700 -> 10p ... (4)
(4) - (3) : 21u -> 840
1u -> 40
5u -> 200
200 x $0.50 = $100
Ans $100.

Tks!

[alfretztay]

Can someone help me with this ratio problem. Thanks!

Hanson had some one-dollar coins and some fifty-cent coins. The ratio of the number of one-dollar coins to the number of fifty-cent coins he had was 2 : 5. Hanson took 140 fifty-cent coins to the bank and changed these fifty-cent coins for the same value of one-dollar coins. In the end, the number of one-dollar coins to the number of fifty-cent coins he had became 5 : 2. Find the value of the fifty-cent coins Hanson had at first.

one-dollar coins : fifty-cent coins
2u : 5u
+70 -140
5p : 2p

2u +70 -> 5p ... (1)
5u - 140 -> 2p ... (2)
(1) x 2 : 4u + 140 -> 10p ... (3)
(2) x 5 : 25u - 700 -> 10p ... (4)
(4) - (3) : 21u -> 840
1u -> 40
5u -> 200
200 x $0.50 = $100
Ans $100.

Tks!

Glad to help.

[Daddy]

Thank Bigdevil.

[Daddy]

Hi BigDevil,
I do not understand this. How you get the tray 3 time than the box.
Therefore, each tray has 3 times the number of muffins in one box.
Muffins in box -> u
Muffins in tray -> 3u

Thank.

[BigDevil]

Let's say there are u number of muffins in each box.
In 12 boxes, there are 12u muffins.

This same number of muffins are divided into 4 trays.
So each tray has 12u / 4 = 3u muffins.

[Daddy]

Thank alot BigDevil.

[Sruthi]

-can anyone please help me this question