Let his total money be x.
He spent (3/7)*x of his money.
He gave 1/4(x-3/7x) to his sister.
which is : (1/4)*(4/7)*x = (1/7)*x
Now,
How much money he have in the beginning =
(3/7)*x+(1/7)*x+120=x
(4/7)*x+120=x
120=x-(4/7)*x
120=(3/7)*x
x=120*7/3 [cross multiplication]
x=280.
So, Alex had $280 in the beginning.
Answer:
Let the angles have measures 2x,3x,4x
Then 2x+3x+4x = 180
and the rest is easy
Step-by-step explanation:
The y-value of the vertex is positive 3, as shown by the +3 on the right hand side of the equation, and the x-value is -1, from the (x+1)^2 (remember, when the number is inside the brackets, flip the sign) The vertex would be (-1, 3)
If you are looking for a rigorous answer (calculus), we must find the mininum point of the equation: f(x) = (x+1)^2 + 3 f
f'(x) = 2(x+1) = 2x + 2
2x + 2 = 0
x = -1
f(1) = (-1 + 1)^2 + 3
f(1) = 0 + 3 = 3
(-1, 3)
Answer: He'd have to work 15 days.
Step-by-step explanation
With the money in his bank account he'd have to get $173 to be able to pay for the rest of the board. If you were to divide 173 by 12 you'd get 14.4166666667. But you can't have a decimal so you'd round up to get a total of 180. Which is how you get the answer of him needing to work for 15 days.
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