Answer:
First, write 80% as 80100. Then write an equivalent ratio that has the answer in the numerator and 200 in the denominator. 100 x 2 is 200, so 80 x 2 will be the answer. 80 x 2 = 160. The answer is $160.
N=number of nickels
d=number of dimes
q=number of quarters
example
if n:d=3:8
lets say n=3 and d=8
3*8=8*3
so
8n=3d
slightly confusing but go with it, it migh make sense or it might not
n:d=3:8
8n=3d
d:q=4:5
5d=4q
solve for one of them
solve for nickels in first and quarters in second
8n=3d, n=(3/8)d
5d=4q, (4/5)d=q
5n+10d+25q=690
divide by 5 to make it easeir
n+2d+4q=138
sub (3/8)d for n
sub (4/5)d for q
(3/8)d+2d+5(5/4)d=138
(3/8)d+2d+25/4d=138
3/8+2+25/4=
3/8+16/2+50/8=
69/8
(69/8)d=138
times both sides by 8
69d=1104
divide both sides by 69
d=16
16 dimes
sub back
(5/4)d=q
(5/4)16=q
80/4=q
20=q
(3/8)d=n
(3/8)16=n
48/8=n
6=n
6 nickles
16 dimes
20 quarters
yah
Answer:
x=-1/4 thats the answer alternative
