Fiora starts riding her bike at 20 mi/h. after a while, she slows down to 12 mi/h, and maintains that speed for the rest of the trip. the whole trip of 70 mi takes her 4.5 h. for what distance did she travel at 20 mi/h?

Answer : Distance, d = 40 mi.

Explanation :

It is given that,

Fiora starts riding her bike at 20 mi/h. after a while, she slows down to 12 mi/h and maintains that speed for the rest of the trip. the whole trip of 70 mi takes her 4.5 h.

Let for t hours she traveled at 20 mi/h. So, for ( 4.5 - t) h she has traveled with a speed of 12 mi/h.

We know that,

distance covered = speed × time

20 mi/h × t +12 mi/h (4.5 h - t) = 70 mi

t = 2 h

So, the distance covered in 2 h is, d = 20 mi/h × 2 h = 40 mi.

Hence, this is the required solution.

this is poiselle's equation from fluid mechanic in physics. mech eng

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