UGH! RSM John's family visited his grandmother over the weekend. The drive to her house took 2 hours at their usual speed. the trip home took 15 minutes longer because traffic was bad and they had to drive 5 mph slower. How many miles away is john's grandmother's house? will give BRAINLIEST! +10pts!

90 miles!

Step-by-step explanation:

there are two parts to the problem, meaning you'll need 2 equations.

let's call the distance TO the grandma's house d1, and BACK from the grandma's house d2.

KEY:

time TO g'ma house= t1

time FROM g'ma house=t2

(replace the t's with 's' for speed, with the '1' for to, and '2' for from)

(distance is a constant so d1 is always equal to d2).

d1=s1+t1, d2=s2+t2

we know what t1 is. 2 hours.

d1=s1•2

meaning that d2 is also equal to that.

s1•2=(s1-5)•2 1/4

2s1=2 1/4 s1-11 1/4

11 1/4= 2 1/4 s1-2s1

11 1/4 = 1/4 s1

s1 (to g'ma)=45 mph

distance is speed times time.

so 45•2 (hr) = 90.

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents