1. 7.4B HW Answers

2. 2. Jose has $2. 45 in nickels and dimes
2. Jose has $2.45 in nickels and dimes. He has ten more nickels than dimes. How many of each does he have?
0.05n d = 2.45
5n + 10d = 245 25
n = d + 10
= =
5(d + 10) + 10d = 245
5d d = 245
15d + 50 = 245
d = 13
15d = 195

3. + (–10) 0.10d + 0.25q = 9.65 d + q = 59 -10d–10q = -590 15q = 375
3. A jar filled with only dimes and quarters contains a total of 59 coins. The value of all the coins in the jar is $ How many quarters are in the jar?
0.10d q = 9.65
10d + 25q = 965 +
(–10)
d + q = 59
-10d–10q = -590
15q = 375
q = 25

4. 4. Ernie has $3. 65 in nickels and dimes
4. Ernie has $3.65 in nickels and dimes. He has 13 more nickels than dimes. How many of each coin does he have?
0.05n d = 3.65
5n + 10d = 365 33
n = d + 13
= =
5(d + 13) + 10d = 365
5d d = 365
15d + 65 = 365
d = 20
15d = 300

5. + (–5) 0.05n + 0.25q = 9.65 5n + 25q = 965 n + q = 65 -5n – 5q = -325
5. A jar filled with only nickels and quarters contains a total of 65 coins. The value of all the coins in the jar is $ How many quarters are in the jar?
0.05n q = 9.65
5n + 25q = 965 +
(–5)
n + q = 65
-5n – 5q = -325
20q = 640
q = 32

6. 6. Tickets to a local movie were sold at $6. 00 for adults and $4
6. Tickets to a local movie were sold at $6.00 for adults and $4.50 for students. If 210 tickets were sold for a total of $1,065, how many student tickets were sold?
6a s = 1065
600a + 450s = +
(–600)
a + s = 210
-600a–600s =
-150s =
s = 130

7. + 25a + 15c = 8415 25a + 15c = 8415 (–25) a + c = 441 -10c = -2610
7. Tickets to a play were sold for $25 for adults and $15 for children. If 441 tickets were sold for a total of $8415, how many children tickets were sold?
25a + 15c = 8415
25a + 15c = 8415 +
(–25)
a + c = 441
-25a –25c =
-10c = -2610
c = 261

8. 8. The Steele Canyon ASB sold advance tickets to the dance for $4 per ticket. Anyone who attended and purchased their ticket at the door had to pay $5 a ticket. A total of 480 students attended the dance and ASB earned $ How many students bought tickets at the door?
4a + 5d = 2100
4a + 5d = 2100 +
(–4)
a + d = 480
-4a – 4d = -1920
d = 180

9. + 3a + 1s = 470 3a + s = 470 (–1) a + s = 292 -a – s = -292 2a = 178
9. Altogether 292 tickets were sold for a high school basketball game. An adult ticket costs $3 and a student ticket costs $1. Ticket sales were $470. How many of each type of ticket were sold?
3a + 1s = 470
3a + s = 470 +
(–1)
a + s = 292
-a – s = -292
2a = 178
89 + s = 292
a = 89
s = 203