Ok so, Since Kelli and her family drove a total of 293 miles in 7 hours, then your equation should be
Now, since you have your ratio you divide 293 by 7 in order to get how many miles were driven in one hour

= 41.85714286 miles/hr
If there are 40 children aged twelve and under and x of them are under three years old, 40 - x aged three twelve years old. From the 92 people that where taken by the company on whale watching trips, 52 are over twelve years old. The equation that best show the total cost, C is
(40 - x)(36) + (52)(48) = C
Rearranging the equation gives,
x = 40 - ((C - 2496)/ 36)
The mean should be about the same, because the sample is random