The formula required to answer this is:

where A is the amount of the principal P after n compounding periods per year at r interest rate (as a decimal fraction).
Plugging in the given values, we get:

Rounding to the nearest dollar, we get $662.00. Therefore a is the best answer choice.
Answer:
155.384615385
Step-by-step explanation:
All sides of an equilateral triangle are equal, so all three sides are 9 cm.
To find h, use the pythagorean theorem. This requires use of only one right triangle, where we use b as our h.
a^2+b^2=c^2
(4.5)^2+b^2=(9)^2
(20.25)+b^2=(81)
b^2=(81/20.25) or 4
square root both sides
b=2
Let x be the total weekly sales.
His salary is $300/week + 1.8% (x), if he wants to earn $570, then:
300 + 1.8%(x) = 570
1.8%(x) = 270
0.018 (x) = 270
and x = 270/0.018 = $15,000
2x + 40
Divide both sides by 2
You get x + 20