We can make two simple equations to express their ages to each other, then solve for one of the variables. Let n be Nojo's age and j be Jacob's age.
n(j) = 84
n - 5 = j
Use substitution to get only one variable in an equation.
n (n - 5) = 84
n^2 - 5n = 84
Since we have n to the power of 2, this equation has two possible answers, but since we are given four possible answer, just substitute them in the equation until one makes the left side equal 84.
<span>n^2 - 5n = 84
</span>12^2 - 5 (12) = 84
144 - 60 = 84
84 = 84
The answer is C = 12
The 10 tons should have 37.9% cement.
Let the 25% mixture be x tons
Then the 68% mixture will be (10 -x) tons.
Using formula for mixtures:
Let p for percentage and w for weight in tons.
p₁w₁ + p₂w₂ = pw
25*x + 68*(10-x) = 37.9*10
25x + 680 - 68x = 379
680 - 43x = 379
680 - 379 = 43x
301 = 43x
43x = 301
x = 301/43
x = 7
Recall that x, was for the 25% mixture, 7 tons.
a) For the 68% mixture, = 10 - x = 10 -7 = 3 tons.
b) For the 25% mixture = x = 7 tons.
Answer:
230
Step-by-step explanation:
Answer:
y=-6/19x+1
Step-by-step explanation:
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Answer:
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