Answer:
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Step-by-step explanation:
Answer:
Step-by-step explanation:
The rock will hit the surface when its height equals zero.
t^2-8t-10=0
t^2-8t=10
t^2-8t+16=10+16
(t-4)^2=26
t-4=+(26^(1/2))
t=4+(26^(1/2))
t=9.1s
Answer:
10
Step-by-step explanation:
x = Edith's age = 20 years
y = Ronald's age
x = 20 = y/4
y = 20×4 = 80 years
in z years we have
(x + z) = (y + z)/3
(20 + z) = (80 + z)/3
3(20 + z) = 80 + z
60 + 3z = 80 + z
60 + 2z = 80
2z = 20
z = 10
in 10 years Edith's age will be 1/3 of Ronald's age.
then Edith will be 30, and Ronald will be 90.
30 = 90/3
correct.
Answer:
Number of rats : Food weight = 1 : 5
Step-by-step explanation:
Number of rats in the group = 9
Weight of food carried away by them = 45 kg
Ratio of the number of rats and food weight = 
= 
= 
= 
Therefore, Number of rats : Food weight = 1 : 5