Can someone help me I have two more other questions they are 15 points each I just posted them right now! Thanks so much

$10 coins: 21

$20 coins: 24

Step-by-step explanation:

heyy me again

So we can create 2 equations where

x = number of $10 coins

y = number of $20 coins:

x + y = 45

10x + 20y = 690

we can move equation 1 around so that we can get a value of x

x = 45 - y

now we can substitute x into the second equation

10(45 - y) + 20y = 690

450 - 10y + 20y = 690

10y = 240

y = 24

Now plug in y back into the first equation

x = 45 - y

x = 45 - 24

x = 21

step-by-step explanation: