Question

Jackson and Jonah are both swimming. Jackson swims at 1350 meters per hour. Jonah swims at a speed of 1250 millimeters per second. Who swam faster in cm/min? How much faster?
A. Jackson, 2250 cm/min
B. Jonah, 7500 cm/min
C. Jackson, 5250 cm/min
D. Jonah, 5250 cm/min

Answer 1

For this question we will use the following relations.

100 centimeters=1 meter (or 1 centimeter= 0.01 meter)

10 millimeter=1 centimeter (or 1 mm=0.1 cm)

60 minutes = 1 hour (or 1 min=$\frac{1}{60}$ hour)

Now, Jackson's speed is 1350 meters per hour. This can be converted to cm per minute as follows:

$\frac{1350 m}{1 h}=\frac{1350\times 100 cm}{60 min}=2250 cm/min$...Equation 1

Likewise, Jonah's swim speed in cm/min can be calculated as:

$\frac{1250 mm}{1 s}=\frac{1250\times 0.1 cm}{\frac{1}{60}min } =\frac{125\times 60 cm}{1 min}=7500cm/min$...Equation 2

As we can see clearly after comparing Equation 1 and Equation 2, Jonah's swim speed of 7500 cm/min is faster than that of Jackson.

Thus, option B is correct.