To find Jenny's age as a percentage of her great grandmother's age :

Answer:
1/3
Step-by-step explanation:
60-90 is 30 numbers, right? So it is 30/90, or 1/3
(5*7) - (5*4) = 35 - 20 = 15
you "distribute" the 5 but multiplying it to both numbers in the parentheses, and doing the subtraction.
Answer:
9/2
Step-by-step explanation:
perpendicular lines have slopes that are opposite and reciprocal
the reciprocal of -2/9 is 9/2