coins confusion!!?

Question

The ratio of ten-cent coins to twenty-cent coins in a puse is 3:5.If 6 twenty cent coins are taken out of the purse,the ratio of ten cent coins to twenty cent coins becomes 1:1.How many ten cent coins are there in the purse??

explanation would be very helpful.
thanks!

Answer 1

9 tens 15 twenties

Answer 2

First of all, where did you get the twenty cent coins?

Let
a = number of ten cent coins
b = number of twenty cent coins

We have

a/b = 3/5
a/(b-6) = 1

Clear the denominator in the second equation.

a = b - 6
b = a + 6

Substitute this back into the first equation.

a/b = 3/5
a/(a + 6) = 3/5

Clear the denominators.

5a = 3(a + 6)
5a = 3a + 18
2a = 18
a = 9

There are 9 ten cent coins in the purse.

Answer 3

Let x = number of 10-cent coins
y = number of 20-cent coins

Ratio of 10-cent coins to 20-cent coins is 3:5

x/y = 3/5 (eq. 1)

If 6 20-cents are taken out, the ration becomes 1: 1

x/y-6 = 1/1 (eq. 2)
_________________________

x/y = 3/5 (eq. 1)
x/y-6 = 1/1 (eq. 2)
____________

x/y = 3/5 (eq. 1)
Cross multiply
5x = 3y
Solve for x
5x/5 = 3y/5
x = 3/5y
Substitute the value of x in eq. 2

x/y-6 = 1/1
3/5y / y-6 = 1/1
Cross multiply
3/5y = y -6
3/5y - y = -6
3/5y - 5/5y = - 6
-2/5y = -6
Multiply both sides by -5/2
-5/2(-2/5y = -6)
y = 30/2
y = 15 ==> number of 20-cent coins
Substitute the value of y in eq. 1 to find x
x/y = 3/5
x/15 = 3/5
Cross multiply
5x = 45
5x/5 = 45/5
x = 9 ==> number of 10-cents coins
___________________
To check
x = 9, y = 15

x/y = 3/5
9/15 = 3/5
Cross multiply
9*5 = 15*3
45 = 45

Answer 4

ten: number of ten cent coins
twenty: number of twenty cent coins

ten/twenty=3/5
=> 5*ten=3*twenty(I)

(twenty-6)/ten=1/1
=>twenty-6=ten(II)

from (I) and (II) => 2/5 twety=6 => twenty=15

=> ten=9 coins

Answer 5

10 coins

Answer 6

9.
Before: 10c:20c--3:5
After: 10c:20c--3:3=1:1
2u=6
1u=3
3u=9

Answer 7

ok i will tell u that the people that have answered this quisetion r wrong! they r way off.