Final answer:
By converting the time and rate, we find that Francine can decorate 10.5 cakes in one hour, given her rate of 3 1/2 cakes per 20 minutes.
Step-by-step explanation:
The question asks us to calculate how many cakes Francine can decorate in one hour, given her rate of decorating 3 1/2 cakes in 20 minutes. First, we find out how many 20-minute intervals there are in an hour, which is three (since 60 minutes divided by 20 minutes equals 3). Then, we multiply the number of cakes Francine can decorate in 20 minutes (3 1/2) by the number of 20-minute intervals in an hour (3) to find the total number of cakes she can decorate in one hour.
To make the calculation easier, we can convert 3 1/2 cakes to a decimal, which gives us 3.5 cakes. Therefore, Francine can decorate 3.5 cakes x 3 = 10.5 cakes in one hour.