All u need is here in the pic

for problem 1 it is 2nd one

for problem 2 1200 people bought online cause 15*1200= 18000 18000+2500= 20500 so it would be 3rd one 550

then problem 3 would be 4th one 72

Step-by-step explanation:

the problem 2 one is confusing so it might be wrong hope not cross fingers!!!

a

step-by-step explanation:

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: