Question

Over the last 2.5 years, the water level in a lake has changed by -0.3 feet per year. Scientists predict that the water level will continue to go down for the next 5 years at a rate of 0.4 feet per year.

Based on this information, Andrew made several claims. Determine whether each of the claims he makes is true or false.

A
In the last 2.5 years, the water level has decreased 0.75 feet.

True False
B
The overall change of the water level after 7.5 years will be -2.75 feet.

True False
C
The change in water level each year for the next 5 years will be -0.4 feet.

True False
D
The overall change in water level for the next 5 years is equal to 5(0.4).

True False

Answer 1

Explanation:

A)

"In the last 2.5 years, the water level has decreased 0.75 feet."

In the very first statement it has been stated that over the last 2.5 years, the water level in a lake has changed by -0.3 feet per year. That means in the last 2.5 years , total decrease in level is as follows

2.5 x - 0.3 = - .75 ft .

So the statement is true.

B)

"The overall change of the water level after 7.5 years will be -2.75 feet."

This statement appears to be false based on information provided

No prediction regarding rate of decrease for a period beyond 5 year has been made so any statement with respect to a timeline of 7.5 years may turn out to be false.

C)

"The change in water level each year for the next 5 years will be -0.4 feet. "

This statement prima-facie appears to be true because rate of decrease stated in the statement is 0.4 ft /year for next 5 years .

D )

"The overall change in water level for the next 5 years is equal to 5(0.4)"

this statement is true

as change in one year = .4

change in 5 years = 5 x .4