Question

At higher elevations water boils at lower temperatures. The temperature at which water boils is called the boiling point of water. At sea level the boiling point of water is 100oC, while at 2 kilometers of elevation (about 6550 feet) the boiling point of water is 94oC. The function that gives the boiling point of water in oC, B
B
, at an elevation of x
x
kilometers is B(x)=100−3.5x
B(x)=100-3.5x
.

Determine the elevations at which the boiling point of water is between 84 oC and 88 oC. Give your answer accurate to 1 decimal place.


The boiling point of water is between 84 oC and 88 oC when the elevation is between

Answer 1

Answer:

  The boiling point of water is between 84 °C and 88 °C when the elevation is between 3.4 and 4.6 km.

Step-by-step explanation:

You want x such that ...

  84 ≤ B(x) ≤ 88

  84 ≤ 100 -3.5x ≤ 88 . . . . substitute for B(x)

  -16 ≤ -3.5x ≤ -12 . . . . . . . .subtract 100

  4.6 ≥ x ≥ 3.4 . . . . . . . . . . .divide by -3.5; this reverses the inequality