Question 954026
Q=quarters; D=dimes=2Q; N=nickels=D+25=2Q+25
$0.25Q+$0.10D+$0.05N=$4.00 Substitute for D and N.
$0.25Q+$0.10(2Q)+$0.05(2Q+25)=$4.00 
$0.25Q+$0.20Q+$0.10Q+$1.25=$4.00 Subtract $1.25 from each side.
$0.55Q=$2.75 Divide each side by $0.55
Q=5 ANSWER 1:There were 5 quarters
D=2Q=10 ANSWER 2: There were 10 dimes.
N=D+25=35 ANSWER 3:There were 35 nickels.
CHECK:
$0.25Q+$0.10D+$0.05N=$4.00 
$0.25(5)+$0.10(10)+$0.05(35)=$4.00 
$1.25+$1.00+$1.75=$4.00
$4.00=$4.00