The answer is 1989 because that’s how much I know
For me cross multiplying works really well.
Answer:
3.375
Step-by-step explanation:
A mountaineer climbed 1000 feet at a rate of x feet/hour
1000 = x ( t 1 ) eq1
5000 = X ( t 2) eq2 ( he climbed additional at different rate )
the rate was 10 feet / hour less than twice the first rate
X = 2x - 10 eq3
take eq1 and eq 2
( total time = t 1 + t 2 = T)
T = 1000/x + 5000/X
but X = 2x-10
T = 1000/x + 5000/( 2x -10)
T = 1000/x + 5000/( 2(x-5))
T = 1000/x + 2500 / (x-5)
