Answer:
40
Explanation:
Let the numbers of purple marbles be P and yellow marbles be y
Given
The bag contains purple and yellow marbles = 52
That’s
P + y = 52
Also, the number of purple marbles P is 4 more than 3 times the number of yellow marbles y
That’s
P = 4 + 3y
We now have two equations
1. P + y = 52
2. P = 4 + 3y
Substitute 4 + 3y for P in equation 1
We now have
4 + 3y + y = 52
4 + 4y = 52
Subtract 4 from both sides to eliminate 4 on the left side
4 - 4 + 4y = 52 - 4
4y = 48
Divide both sides by 4 to get y
4y/4 = 48/4
y = 12
Recall
P = 4 + 3y
So
P = 4 + 3 x 12
P = 4 + 36
P = 40
There are 40 purple marbles in the bag