Answer:
12
Step-by-step explanation:
x = number of $1 bills
y = number of $5 bills
z = number of $10 bills
We know that:
x + y + z = 25 (total amount of bills)
x + 5y + 10z = 100 (total amount of money)
y = 4z (Given)
Substitute the third equation into the first one.
x + 4z + z = 25
x = 25 - 5z
Put this into the second equation.
(25 - 5z) + 5 (4z) + 10z = 100
Simplify and solve.
25 - 5z + 20z + 10z = 100
25z + 25 = 100
25z = 75
z = 3
Substitute this into y = 4z
y = 4 * 3
y = 12
So, there are 12 $5 bills.
Answer:

Step-by-step explanation:
[in picture]
Answer:
7, 7.1, √51, 7.2
Step-by-step explanation:
√51 is 7.14
440...marked down by 30% means u pay 70%
70% of 440 = 0.70(440) = 308
308 ..marked down by 10% means u pay 90%
90% of 308 = 0.90(308) = 277.20 <== price after markdowns