Question

231 students of the Brooklyn Public Library went on a field trip. Some students rode in vans that hold 7 students each, and some students rode in buses that hold 25 students each. How many of each type of vehicle did the students ride in if there were 15 total vehicles? *

Answer 1

We have the next information

In total, we have 231 students

van--- 7 students

bus - 25 students

in total, we have 15 vehicles

So our first equation is

x+y=15

where

x is the number of vans

y is the number of buses

The second equation is

7x+25y=231

so we will isolate the x of the first equation

x=15-y

then we substitute this equation in the second equation

7(15-y)+25y=231

105-7y+25y=231

then we sum like terms

18y=126

then we isolate the y

y=126/18

y=7

Then for the value of x we use the equation with the x isolate and we substitute the value of y

x=15-7=8

Therefore the answer is 8 vans and 7 buses