An electric heater uses 3 / 5

watts of power each hour. How many watts of power will the heater use in

1 / 2

hour?

a. 3/10

b. 11/10

c. 3/5

d. 11/5

This question could not come from any school source. If it did,

then you should always be suspicious of anything that comes

from that source. The question contains a fundamental mistake,

and misleads the student.

"Power", measured in "watts", is a rate, not a quantity. It tells

how fast you're using energy. You don't use some watts this

morning and some more watts this afternoon. That's like saying

that you'll drive some miles per hour today, and then you'll drive

some more miles per hour tomorrow. It doesn't work that way.

The heater doesn't use up some amount of watts. It uses up

some amount of energy. "Watts" is the measure of how fast

or slowly it uses up the energy.

This question makes sense if you get rid of the 'watts' and call it

'pints of milk' instead.

"My cats drink 3/5 pint of milk each hour.

How many pints of milk will they drink in 1/2 hour?"

(1/2 hour) x (3/5 pint/hour)

= (1/2 x 3/5) (pint)

= 3/10 pint.

In this question, all the vital information's required to reach the solution is already given. Based on those information's the answer to the question can be easily reached. Let us first write down all the information's given.

Amount of power used by the electric heater in 1 hour = 3/5 watts

Then

Amount of power used by the electric heater in 1/2 hour = (3/5) * (1/2) watts

= (3 * 1) / (5 * 2) watts

= 3/10 watts

So 3/10 watts of power is required by the electric heater in 1/2 an hour. The correct option among all the options given in the question is option "a".