Which is true statement about 7 and 14

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

Having a hard time understanding this question (see attachment).

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.