Problema Solution
A bag contains yellow marbles and blue marbles, 49 in total. The number of yellow marbles is 7 less than 3 times the number of blue marbles. How many yellow marbles are there?
Answer provided by our tutors
Let
y = the number of yellow marbles, y>0
b = the number of blue marbles, b>0
A bag contains yellow marbles and blue marbles, 49 in total:
y + b = 49
The number of yellow marbles is 7 less than 3 times the number of blue marbles:
y = 3b - 7
By solving the system of equations:
y + b = 49
y = 3b - 7
........
........
y = 14 yellow marbles
b = 35 blue marbles
There are 14 yellow marbles.