There is a device called a thermometer for that...
4. Would be A
5. Would be D
I hope this helped you :)
Answer:
Hi bro /siso plss post in the English Hope it helpfull too
Well to find this out you need to make an equation
s+7=j
So for example if Johnny's sister is 15 then Johnny would be 22 because
s(sister's age) +7(number of years difference between their ages)=22(Johnny's age)