Lucy has 68 books. This number of books is 70% more than the number of books she had last year.
How many books did Lucy have last year?

Lucy had 40 books last year.

Step-by-step explanation:

assuming 100% is the percent;

100% + 70%

100 : x

170 : 68

cross multiply = 170x = 100 x 68

————-

170 170

cancel 170/170

therefore x = 100 x 68 divided by 170

result is 40

3.4 pizzas

step-by-step explanation:

given is a scatter plot showing number of pizzas sold during weeks for different issues of coupon

y represents number of pizzas sold and x number of coupons issued

y is marked verticaly and x horizontally

the trend line is given as

y =3.4x+43

this says that even when no coupon is issued pizzas sold will be 43

and rate of change of pizza sold for 1 unit of coupon = slope = 3.4

i.e. when x increases by 1 unit y increases by 3.4 units

hence for each additional coupon issued 3.4 pizzas more will be sold

take it another