A machine costs m dollars per day to maintain and n cents for each unit it produces. If the machine is operated 7 days a week and produces r units in a week, which of the following is the total cost, in dollars, of operating the machine for a week?
A)7m + 100nr
B)7m + nr / 100
c) 7m+nr
D)7m+100nr /100
E)700mnr
OA
B
A machine costs m dollars per day to maintain
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You're missing part of the question here.canbtg wrote:A colony of ants increases its population by 4 percent. If after this increase, bacteria deplete the population by , the new ant population is what percent of the original ant population?
A)16%
B)26%
C)29%
D)50%
E)78%
We need to know the percent reduction caused by the bacteria.
Cheers,
Brent
Hi Brent , Sincere apologies . I could solve the previous question , however , stuck at another one . So I just edited this post with a new question . Appreciate if you could help me to solve it.Brent@GMATPrepNow wrote:You're missing part of the question here.canbtg wrote:A colony of ants increases its population by 4 percent. If after this increase, bacteria deplete the population by , the new ant population is what percent of the original ant population?
A)16%
B)26%
C)29%
D)50%
E)78%
We need to know the percent reduction caused by the bacteria.
Cheers,
Brent
Regards !
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TOTAL cost = maintenance cost + production costcanbtg wrote:A machine costs m dollars per day to maintain and n cents for each unit it produces. If the machine is operated 7 days a week and produces r units in a week, which of the following is the total cost, in dollars, of operating the machine for a week?
A) 7m + 100nr
B) 7m + nr/ 100
C) 7m + nr
D) 7m + 100nr/100
E) 700mnr
This machine costs m dollars per day to maintain, and the machine is operated 7 days.
So, the total maintenance cost = 7m dollars
The machine costs n CENTS for each unit it produces.
Since the question asks for the total cost in DOLLARS, we can convert n CENTS to n/100 DOLLARS
If the machine produces r units, then the total production cost = (n/100)(r) = rn/100 dollars
So, TOTAL cost = 7m + rn/100 dollars
Answer: B
Cheers,
Brent
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Hi canbtg,
This question can also be solved by TESTing VALUES.
We're told that there are 2 costs with running a machine:
M DOLLARS per day to maintain it
N CENTS per unit that it produces
We're told that R units are produced over the course of 7 days. We're asked for the cost, IN DOLLARS of operating the machine during that time.
Let's TEST VALUES:
M = 2
N = 3
R = 200
Over the course of 7 days, we spent ($2/day)(7 days) to maintain the machine and (3 cents)(200 units) on the units. Thus, we spent $14 + $6.00 = $20
The only answer that matches is B
GMAT assassins aren't born, they're made,
Rich
This question can also be solved by TESTing VALUES.
We're told that there are 2 costs with running a machine:
M DOLLARS per day to maintain it
N CENTS per unit that it produces
We're told that R units are produced over the course of 7 days. We're asked for the cost, IN DOLLARS of operating the machine during that time.
Let's TEST VALUES:
M = 2
N = 3
R = 200
Over the course of 7 days, we spent ($2/day)(7 days) to maintain the machine and (3 cents)(200 units) on the units. Thus, we spent $14 + $6.00 = $20
The only answer that matches is B
GMAT assassins aren't born, they're made,
Rich