distance = rate x time

At 54 mph

d = 54t {distance = rate x time}

At 57 mph

d = 57(3.5 - t) {rate x time.....time is the total time (3.5) - the 54 mph time (t)}

54t + 57(3.5 - t) = 195 {combined distances equal 195}

54t + 199.5 - 57t = 195 {used distributive property}

-3t + 199.5 = 195 {combined like terms}

-3t = -4.5 {subtracted 199.5 from each side}

t = 1.5 {divided each side by -3}

**time at 54 mph is 1.5 hours
**

3.5 - t {time at 57 mph}

= 3.5 - 1.5 {substituted 1.5, in for t, into 3.5 - t}

= 2 {subtracted}

**time at 57 mph is 2 hours***- Algebra House*
**
**