I think the answer is 17.5 years
Answer:
s = -7.8
Step-by-step explanation:
from the question 12=10(s+4)+50
<u>first step</u>
open the bracket and evaluate for the value of s
12=10(s+4)+50
12 = 10s + 40 + 50
12 = 10s + 90
collect or combine the like terms
12-90 = 10s
-78 = 10s
divide both side by 10
-78/10 = 10s/10
-7.8 = s
therefor s = -7.8
Answer:
The function is A = 10√r
Step-by-step explanation:
* Lets explain the meaning of direct variation
- The direct variation is a mathematical relationship between two
variables that can be expressed by an equation in which one
variable is equal to a constant times the other
- If Y is in direct variation with x (y ∝ x), then y = kx, where k is the
constant of variation
* Now lets solve the problem
# A is varies directly with the square root of r
- Change the statement above to a mathematical relation
∴ A ∝ √r
- Chang the relation to a function by using a constant k
∴ A = k√r
- To find the value of the constant of variation k substitute A and r
by the given values
∵ r = 16 when A = 40
∵ A = k√r
∴ 40 = k√16 ⇒ simplify the square root
∴ 40 = 4k ⇒ divide both sides by 4 to find the value of k
∴ 10 = k
- The value of the constant of variation is 10
∴ The function describing the relationship of A and r is A = 10√r
The actual distance between the two towns is 15 miles.
