Answer:
Step-by-step explanation:
Sixth graders can have 4 groups of 4
seventh graders can have 5 groups of 4
One week = 3 dolls
two weeks = 3 × 2 dolls
three weeks = 3 × 3 dolls
four weeks = 3 × 4 dolls
five weeks = 3 × 5 dolls
'w' weeks = 3 × w dolls
'w' weeks = 3w dolls
Initial number of dolls = 254 dolls
Number of dolls after 'w' weeks = 254 + 3w
Matthew is 12 and Elizabeth is 7