We can compare by converting Johnny's reading time into the same unit of Jacky's, hours.
There are 60 minutes in an hour, so use this:

15 < 20, so Johnny read faster. This is 5 pages faster per hour than Jacky.
Answer:
7.5
Step-by-step explanation:
multiply like normal math . then add the decimal point after 1 number
Step-by-step explanation:
x+x squared =42. The square of the number is the number square. By my incredibly accurate guess and check strategy (works most of the time )6*6 = 36+6=42
It is 4900mm^3 because there are 1000mm^3 in one 1cm^3.
If you do 10^3 (10 mm) it gives you 1000mm^3.
Hope this helps.