Agroup of tourists were supposed to cover an 18 km distance in a certain amount of time. however, they actually traveled at a speed which was .5 km/hour greater than what they had actually planned and thus arrived a half an hour early. what speed had the tourists planned to go at?

The speed that they planed to go, was 4 km/h.

Step-by-step explanation:

Let tourists planned to go at the speed of x km/h,

After increasing the speed by 0.5 km/h,

Their new speed = ( x + 0.5 ) km/h,

Total distance = 18 km,

According to the question,

The time taken at the speed of x - time taken at the speed of (x+0.5) = 1/2 hours,

( Because, Time = distance / speed ),

⇒ x - 4 = 0 or 2x + 9 = 0  

x = 4 or 2x = -9  

x = 4 or x = -9/2 = -4.5 (not possible)

Thus, the speed that they planed to go = x km/h = 4 km/h

hello from mrbilldoesmath!

answer:

x - 3

discussion:

x^2 - 9 = (x-3) (x+3)   so

(x^2-9)/ (x + 3) = x-3

you,

mrb