Answer:
A
Step-by-step explanation:
how long is the ball in the air ?
that is the same as asking : after how many seconds will the ball hit the ground (= reach the height of 0) ?
so, that means we need to find the zero solution of h(t).
at what t is h(t) = 0 ?
when at least one of the factors is 0 :
2(-2 - 4t)(2t - 5)
we have 3 factors
2 : can never be 0.
(-2 -4t) : can only be 0 for negative t, which does not make sense in our scenario (we cannot go back in time, only forward).
(2t - 5) : is 0 when 2t = 5 or t = 2.5
so, A is the right answer.
FYI : the starting height (on the hill) is given by t = 0 :
2(-2 - 0)(0 - 5) = 2×-2×-5 = 20 ft
Greetings!
The best way to compare fractions is to find the LCM (The Lowest Common Denominator) of each of the fractions. This can be done simply by listing the multiples of the denominators.
Multiples:
3: 3,6,9,12,15,18,21,24,27...210,213
10:10,20,30,40,60,70,80...210,220
6: 6,12,18,24,30,36,42,48...210,216
7: 7,14,21,28,35,42,49...210,217
The LCM is 210:
3*70=210
10*21=210
6*35=210
7*30=210
Now, we must do what we do the denominators to the numerators:
1*70=70
70/210
2*21=42
42/210
1*35=35
=35/210
2*30=60
=60/210
The fraction with the largest numerator has the greatest value; In this case it 1/3 or 70/210.
Hope this helps.
-Benjamin
