
Help with bar model
Help with bar model
Let 3u be the amount sally has
Amount ruby has originally = 3u x 5 = 15u
Ruby’s new amount = 7u (sally had 3/7 of ruby’s new amount)
15u-80 = 7u
8u = 80
u = 10
Ruby had 15u = 15×10 = $150
Ruby [ ][ ][ ][ ][ ] x 5 = 15u
Sally [ ] x 3 = 3u
Sally remains the same but fraction has changed to 3/7
Ruby [ ][ ][ ] = 7u
Sally [ ][ ][ ] = 3u
Spent = 80
15u–7u = 8u = 80 => u =10
Hence at first Ruby has 15u = 15 x 10 = $150
Ruby had 5 times as much money as Sally. So we start with this:Sally had 3/7 as much as Ruby in the end. So we modified the diagram by cutting each block into 3 smaller pieces.
Now Sally had 3 pieces and Ruby had 3 x 5 = 15 pieces. Enumerate the 3 pieces for Sally and 7 pieces for Ruby. Remaining 15 - 7 = 8 pieces is the $80 spent. So each piece is $10. Ruby had $150 at first. CHECK: Ruby Sally At first 150 150/5 = 30 Later 150-80=70 30 Fraction = 30/70 = 3/7