Let p = the number of pennies
let q = the number of quarters
p + q = 23
0.01p + 0.25q = 3.11
(Pretend you're multiplying 15×20)
1. Start at 0 (obviously)
2. Go 20 numbers to the left and stop (if you're drawing or writing on the number line, make a line vertically to show that's where you stopped for the first 20
3. Do this 14 more times and keep on going to the right
I got 24 there is 24 red rocks and 18 black rocks.What I did was divide 42 by 2 and got 21 then added 3 and got 24. So hope this helps :D
Answer:
the answer is c.
Step-by-step explanation:
4 x 5 + 7 x 7 = 69
4 x 3 + 7 x 9 = 75