Question

-7, -12, -7, -22 solve this question please fast iam not com answer and explain me in maths this question ​

Answer 1

Answer:

Step-by-step explanation:

Let's change the problem to one that only involves two people, which is probably the original intent.

J can ride his bike 8 mph faster than A can ride. It takes A 3 hours longer than J to ride 48 miles. How fast can J ride?

Let r = rate that J rides, in miles per hour.

Then rate that A rides is (r – 8).

distance = rate * time

time = distance/rate

Time taken by J to ride 48 miles = 48/r.

Time taken by A to ride 48 miles = 48/(r – 8).

But A's time is 3 hours more than J's time.

48/(r – 8) = 3 + 48/r

Solve that for r.

48/(r – 8) = 3r/r + 48/r

48/(r – 8) = (3r + 48)/r

Multiply both sides by (r – 8)r.

48(r) = (3r + 48)(r – 8)

48r = 3r2 – 24r + 48r – 384

0 = 3r2 – 24r – 384

0 = r2 – 8r – 128

0 = (r – 16)(r + 8)

So r = 16 mph or r = –8 mph.

J riding 48 mi at 16 mph takes 3 hours.

A riding 48 mi at 8 mph takes 6 hours, which indeed is 3 hours longer.

Just disregard the negative speed answer.

The reason problems like this appear is because they are originally written with boring names like James and Alan, then textbook writers are asked to change the names to be more multiculturally inclusive. That should simply mean a quick find-and-replace scoped just to the problem. But if instead it is done by hand errors creep in, or later editors change names again without following through to change every instance. The result is the technically silly unsolvable problem.