Two numbers are such that the ratio between them is 3: 5. if each is increased by 10, the ratio
between the new numbers so formed is 5: 7. find the original numbers.

Step-by-step explanation:

We have two variables, x and y.

So, we now know that    

So then,

So then the numbers are 15 and 25

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