Answer:
28 seconds
Explanation:
Find when second substance reaches boiling point of water.
1. What is the boiling point of water?
100°. This is common knowledge, just memorize.
2. How fast does the second substance heat up?
"twice the rate of 1.8°C per second"
2 X 1.8°C per second
= 2 X 1.8°C/s
= 3.6°C/s
3. How long until the second substance will reach boiling point?
Model the situation with an equation in slope-intercept format (y=mx+b):
y = 3.6x + 0
m represents the slope or rate of increase, rate of heating up
b represents the y-intercept or initial value, starting temperature
Since the starting temperature is 0, we don't need to include it.
y = 3.6x
y represents the temperature and x represents time in seconds.
The temperature we want to find is 100.
Substitute y for 100.
y = 3.6x
100 = 3.6x
To find the time in seconds, isolate x.
100 = 3.6x
100/3.6 = x
x = 28 (The number is rounded up from 2.77777)
Therefore, it takes 28 seconds for the second substance to reach the boiling point of water.