I need help with this problem, but i don't want someone to just give me the answer. i need it to be taught step-by-step to me because for some reason i can't understand how everyone tells me to do it. i need to learn this as I've been on this one test for the past 2 weeks. I've been trying to find a tutor or something that will actually help me the way i need to be helped. so please, just give me a simple answer that will help me with the 3 other questions after it. the lesson name is called solving real world systems of equations via elimination.
here is the question:

jared bought 7 cans of paint. a can of red paint costs 3.75. a can of black paint costs 2.75. jared spent 22.25 in all. how many cans of black (b) and how many cans of red (r) did he buy?

r+b=7

3.75 + 2.75 = 22.25

this is a lesson in 8th grade math.