Answer:
The bottom question is wrong. You have to multiply 8 to get the amount earned. But the rest is correct.
Step-by-step explanation:
6.25 x 8 = 50
12.5 x 8 = 100
18.75 x 8 = 150
25 x 8 = 200
31.25 x 8 = 250
Loga x=n ⇔ a^n=x
log₇ 21=x
x=log ₇ 21
x=ln 21 / ln7=1.564575034...
Answer: x=log₇ 21
3c = 12.69
where c = # of greeting cars