Answer:
Step-by-step explanation:
Biking is x and bussing is y. We know that the total distance is 325. Thus, the first equation in this system is
x + y = 325 (which says that the km traveled by bike plus the km traveled by bus totaled 325 km).
We also know that the pair biked 75 km more than they rode, giving us the second equation in our system:
x = y + 75. Now we use simple substitution and plug y + 75 in for x in the first equation:
(y + 75) + y = 325 and
2y + 75 = 325 and
2y = 250 so
y = 125 km. They rode the bus for 125 km and biked for 325 - 125 which is 200. And the difference is 75 km, as it should be!