Answer:
a) t = 0.54 seconds
b) t = 8 seconds
Step-by-step explanation:
Given in the question the equation
h = 40t - 5t²
<em> where h is height in meters</em>
<em> t is time in seconds</em>
<em />
Time it took to reach 20 meters
20 = 40t - 5t²
-5t² + 40t - 20 = 0
by using quadratic formula for factorisation
<h3>t = (-b± √(b)² - 4(a)(c) ) / 2(a)</h3>
t = 0.54 (upward motion)
or
t = 7.46 (downward motion)
b) Time it took to reach the ground
at ground h = 0
So,
0 = 40t - 5t²
t(40 - 5t ) = 0
t = 0 (at starting point)
or
40 -5t = 0
5t = 40
t = 40 /5
t = 8 seconds
60 because area of a rectangle is l*b*w. So 6*2*5 will equal 60
-- It takes 10 workers 3 days to build 1 house.
so
-- It takes 10 workers 1 day to build 1/3 of a house.
so
-- It takes 1 worker 1 day to build 1/30 of a house.
You got 15 workers and you need 4 houses ?
Well, as we just calculated . . .
-- It takes 1 worker 1 day to build 1/30 of a house.
so
-- It takes 15 workers 1 day to build 15/30 = 1/2 of a house.
so
-- It takes 15 workers 2 days to build 1 whole house.
so
-- It takes 15 workers 8 days to build 4 houses.
Answer:
the answer is D.
Step-by-step explanation:
.............
Answer:
-1
Step-by-step explanation:
5(-5) + 6(4)
-25 + 24 = 1
