A machine, working at a constant rate, manufactures 36 staplers in 28

If the machine makes 36 staples in 28mins, then how many staples would it make in 105mins
36staples ---> 28mins
y staples ---> 105mins

y = 36 x 105 /28
y = 135
Answer C

The rate of the machine is 540/7.
Multiplying that rate by the time, which is 7/4 gives us 135 staples produced.

Or

we can solve through ratios.
36/28 = X/105
X = 135

Answer: C

Answer = C. 135

Convert Hours in Minutes

Staplers \(= (60+45)* \frac{36}{28} = 135\)

A machine, working at a constant rate, manufactures 36 staplers in 28 minutes. How many staplers does it make in 1 hr 45 min?

A. 125
B. 128
C. 135
D. 144
E. 150

Ans: C.
How?
Well the machine makes 36 staplers in 28 mins. That means every minute it makes 36/28 = 9/7 staplers. It essentially means that it makes more than ~1.2 staplers a min.
1hr 45min is 60mins + 45mins = 105mins

so to rephrase the question, how many staplers can the machine (which makes ~1.2 or 9/7 staplers a min) make in 105 mins?

=\(9/7\) x 105
=9 x 15
=135 staplers.

MAGOOSH OFFICIAL SOLUTION:

Change 1 hr 45 min to 105 min. For this, we need to set up a simple proportion of staplers per time
36/28 = S/105

The absolutely worst thing you could do at this point in the problem is to cross-multiply. That would be a supremely unstrategic move. Instead, cancel before you multiply. For what we can and can’t cancel in a proportion, see this post. We can cancel the factor of 4 in the 36 and 38.
9/7 = S/105

We absolutely cannot cancel any factors between the 9 and 105. That kind of “cross-canceling” is 100% illegal in a proportion. We can cancel the common factor of 7 in the two denominators.
9/1 = S/15.

Now that the fraction is entirely simplified, we can cross-multiply.
S = 9*15 = 135

The machine would be 135 staples in 1 hr 45 min.

Answer: C.

Hi All,

This question is essentially about ratios, so the math can be done in a variety of ways (using fractions, decimals, percents, etc.). Here's a way to get to the correct answer with a little less "math work"

We're told that a machine manufactures 36 staplers in 28 minutes. We're asked how many staplers would be manufactured in 1 hour and 45 minutes.

1 hour and 45 minutes = 60+45 = 105 minutes

28 does NOT divide evenly into 105, but we can still use some estimation here...

(28 minutes)(4) = 112 minutes, so using this estimate, we'll end up with a total that is a little BIGGER than it should be.

(36 staplers)(4) = 144 staplers. Now, we know that this is TOO BIG, so we're looking for an answer that is a little below 144. With a ratio of 36 staplers per 28 minutes, we know that a little more than 1 stapler is made per minute. Since we're dealing with a calculation that is 7 minutes TOO BIG, the difference in staplers would have to be a little more than 7.

144 - (a little more than 7) = about 136

Final Answer:

GMAT assassins aren't born, they're made,
Rich

This is true. As test takers we must remember that answer choices on the GMAT are also resources that we must exploit.

Posted from my mobile device

Solution:

We can set up the following proportion, where x is the number of staplers the machine can produce in 1 hr 45 min, or 105 minutes:

36/28 = x/105

9/7 = x/105

7x = 945

x = 135

Answer: C

A machine, working at a constant rate, manufactures 36 staplers in 28 minutes. How many staplers does it make in 1 hr 45 min?

A. 125
B. 128
C. 135
D. 144
E. 150


It can be written: 36/28 = x/105
so, x = 135

Answer: c