Question 15:
(You need to remember that in a hour there is 60 mins.)
So they arrived at 1:15pm and they stayed there for 2hours and 51mins. So you would add 2 hours on to 1:15 which will bring the time to 3:15, you still have 51 mins to add on. Once you add 51 mins it will bring the time to 4:06.
Question 16:
12 inches = 1 foot
Sarah is 53 inches tall so 53÷12 = 4.416
Round the total to 1d.p so 4.4 ( 4 foot and 4 inches) And add 4 inches on to the total to give you Luke's size which will be 4 feet and 8 inches. However, I'm a bit confused myself because there isn't an option for 4 feet and 8 inches.
Just try your best and tell your teacher you had a go at question 16 but you are still a bit confused they will understand.
Hope this helps!