Let the youngest sister be n years
Lana will be 2n years, as her youngest sister is half her age
The age of the twins separately will be 2n-2 as they are 2 years younger than Lana
So, the equation looks like this:
n + 2n + 2(2n-2) = 45
Now solve for n:
3n + 4n - 4 = 45
7n - 4 = 45
7n = 49
n = 7
So the youngest sister is 7, Lana is 14 and the twins are 12. 14 + 12 + 12 + 7 =45
Answer:15
Step-by-step explanation:
Given
Craftsman sell 10 Jewelry set for $500 each
For each additional set he will decrease the price by $ 25
Suppose he sells n set over 10 set
Earning
Earning 

differentiate to get the maximum value

Equate
to get maximum value



Thus must sell 5 extra set to maximize its earnings.
Answer:
- d and f 2.a and c 3.b and e
Step-by-step explanation:
Answer:
16.075 is the answer.
Step-by-step explanation:
16.075 is the answer. I hope this helps. You divide
64.3/7
=16.075
<span>Let x = # of rides
Plan A: 10 + 3x
Plan B: 20 + x
if x < 5 rides then plan A is better buy
if x = 5 both plans are the same
if x > 5 then plan B is the best buy
Prove:
x = 6 (rides)
plan A: </span>10 + 3x = 10 + 3(6) = 10+18 = $28
plan B: 20 + x = 20 + 6 = $26