Answer:
100
Step-by-step explanation:
In this problem 10 represents 9% of a number. So, to find 90% you must multiply 10 by 10. You do this because 9% times 10 equals 90%; therefore, 100 must be 90%.
This can also be proven through cross multiplication. To set up a proportion put the percent over the number like, 
. Then cross multiply to get the equation, 
. Finally, divide both sides to get x=100.
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:
x = 3, 4, 5
Step-by-step explanation:
Solving the inequality
5x + 2 > 12 ( subtract 2 from both sides )
5x > 10 ( divide both sides by 5 )
x > 2
Thus the only values from the given set which make the inequality true are
x = 3, 4, 5
1+3=4
A counterexample is an a example that proves the statement false.
1+3 are not even numbers but they equal an even one, so it just proved the statement wrong.
Answer:
the answer is 0.083
Step-by-step explanation:
