180 + 30x = 60 + 50x
⇒ 20x = 120
⇒ x = 6 minutes
<span>it will take 6 minutes for Millie to catch up with Ben</span>
Answer:
This is your answer.. you add exponents
The answer to this is letter D
THE SLOPE IS 1 AND THE Y INTERCEPT IS -3, the x is equal to 1, and the -3 is in the place of the y intercept so your answer would be A.
Notice that
13 - 9 = 4
17 - 13 = 4
so it's likely that each pair of consecutive terms in the sum differ by 4. This means the last term, 149, is equal to 9 plus some multiple of 4 :
149 = 9 + 4k
140 = 4k
k = 140/4
k = 35
This tells you there are 35 + 1 = 36 terms in the sum (since the first term is 9 plus 0 times 4, and the last term is 9 plus 35 times 4). Among the given options, only the first choice contains the same amount of terms.
Put another way, we have

but if we make the sum start at k = 1, we need to replace every instance of k with k - 1, and accordingly adjust the upper limit in the sum.

