Final answer:
To find the time it took Lois to ride to her friend's house, we can set up two equations using the formula time = distance/speed. By solving these equations simultaneously, we find that it took Lois 3 hours to ride to her friend's house.
Step-by-step explanation:
To solve this problem, we can use the formula: time = distance/speed. Let's assume that the distance from Lois's house to her friend's house is d. We know that Lois traveled at 10 mi/h to her friend's house and it took her t hours. So, we can write the equation: t = d/10. On the way back, Lois traveled in her friend's car at 25 mi/h and it took her t - 1.5 hours. We can write the equation for the return trip as: t - 1.5 = d/25. Now, we can solve these two equations simultaneously to find the value of t, which will give us the time it took Lois to ride to her friend's house.
Simplifying the equations, we get: d = 10t and d = 25(t - 1.5). Substituting the value of d from the first equation into the second equation, we get: 10t = 25(t - 1.5). Solving for t, we get: t = 3 hours. Therefore, it took Lois 3 hours to ride to her friend's house.