A proportional relationship is also a direct variation.
The general equation of direct cvariation is
y = kx,
where k is a number.
In your case, if k = -1, then y = kx becomes y = (-1)x which is the same as
y = -x
Answer:
4 hours
Step-by-step explanation:
The general formula for distance, rate and time is:
d = rt, where distance is the product of rate multiplied by time
Given that one train is moving at a rate of 70 mph and one is moving at a rate of 62 mph in the opposite direction, the combined distance over time is equal to 528 miles. Using the variable 't' for time:
70t + 62t = 528
Combine like terms: 132t = 528
Divide both sides by 132: 132t/132 = 528/132 or t = 4 hours
There are 2001 items in that set.
So n(A) = 2001
We can individually count them all out, which is very slow and tedious, or we can use the formula
n-m+1
where,
m = starting value
n = ending value
In this case,
m = 0
n = 2000
So,
n-m+1 = 2000-0+1 = 2001
This formula only works if we increase the number by 1 each time (eg: 6, 7, 8, etc)
The answer is 11 sorry if I’m wrong
