Three thermometers are each accurate to within 2 degrees above or below the temperature they actually read. One reads 7°, one reads 9° and one reads 10°.

What is the minimum range in which the true temperature lies?

A 5° - 12°

B 7° - 9°

C 8° - 10°

D 8° - 9°

E 7° - 10°

Kindly also tell the reason of your chosen answer.

Hi!

7° cannot be a true value since it is more than 2° below 10°

10° cannot be a true value since it is more than 2° above 7°

So the minimum range is from 8° to 9°

1 Like

Thanks for the reply. I actually couldn’t understand the sentence in question

“Three thermometers are each accurate to within 2 degrees above or below the temperature they actually read” can you kindly simplify the statement of question?

Hi! I think that sentence means that each of the three thermometers can have an error of up to 2 degrees in either direction from the represented temperature.

For example, if the readings of temperature is 70 degrees, then the actual degrees could range from 68 to 72 degrees.

If it reads 7°, then Actual temp 5°~9°

If it reads 9°, then Actual temp 7°~11°

If it reads 10°, then Actual temp 8°~12°

Therefore, the minimum range will be 8°~9°, option D.