I need help with this ASAP

There are sixteen 15-cent stamps and eight 20-cent stamps.

Step-by-step explanation:

Stamp collector has:

15c stamps

20c stamps

Total value is $4

x($0.15) + y($0.20) = $4.00

The # of 15c stamps is 8 - than 3 * the # of 20c stamps; 15c = 8 - 3c

x = 3y - 8

(3y-8)(0.15)+y(0.20) = $4.00

0.45)y-1.20+(0.20)y = 4.00

(0.65)y-1.20 = 4.00

(0.65)y = 5.20

y = 8

x = 3(8)-8 = 16

There are sixteen 15-cent stamps and eight 20-cent stamps.

Check:

16($0.15)+8($0.20) = $2.40+$1.60 = $4.00

c. 1,233 miles

where is the option given