Answer is
Y = 4 5/7
G = 3 5/7
Step by step
We have 4 Y = yellow circles
We have 3 G = green butterflies
Our equations are
4Y + 3G = 30
G= Y - 1 (because there is 1 less green butterfly than yellow circle)
To solve for Y, substitute G value for G
4Y + 3(Y - 1) = 30 distribute
4Y + 3Y - 3 = 30 combine
7Y -3 = 30 add 3 to both sides
7Y = 33 divide both sides by 7
Y = 4 5/7
To solve for G, substitute Y value for Y
4( 4 5/7) + 3G = 30 distribute
18 6/7 + 3G = 30 subtract 18 6/7 from both sides
3G = 30 - 18 6/7
3G = 11 1/7 divide both sides by 3
G = 3 5/7
Check your work
Sun your Y and G values into your equation
G = Y - 1
3 5/7 = 4 5/7 - 1
3 5/7 = 3 5/7
Yes, they equal so it’s true!
Y = 4 5/7
G = 3 5/7
Problem solved