Question 940274
A plane flies from its base to a fire and back.
 Assuming it travels in a straight line, it travels outward at 240 km/h, and returns at 320 km/h.
 If the plane was away for 35 minutes, find the distance, from the base to the fire.
:
let d = one way distance
:
Write a time equation
time out + time back = 35 min
{{{d/240}}} + {{{d/320}}} = {{{35/60}}} (converted min to hrs)
simplify equation, multiply equation by 10
{{{d/24}}} + {{{d/32}}} = {{{35/6}}}
Multiply equation by a common multiple, 384
384*{{{d/24}}} + 384*{{{d/32}}} = 384*{{{35/6}}}
Cancel the denominators, you have
16d + 12d = 64(35)
28d = 2240
d = 2240/28
d = 80 km from base to fire
:
:
see if this checks out, find the actual time each way
80/240 = .333 hrs
80/320 = .25 hrs
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tot time .583 hrs, convert to min; .583(60) ~ 35 min