Answer
2 buses and 4 vans.
Work Step by Step
Let x be the number of buses and y be the number of vans.
System of equations:
x+y=6
51x+10y=142
y=6-x.
Substitute y value into the second equation:
51x+10(6-x)=142
Distributive property: 51x+60-10x=142
Combine like terms and simplify: 41x=82 => x= 2
When x =2, then 51(2)+10y=142=> 102+10y=142. =>10y=40=>y=4