He needs 160 5-star reviews in a role. We can write a function to solve this problem. His current total stars is 4.4*160=704. Suppose he needs x more 5-star reviews, then his total stars will be 704+5x. 160+x is the new number of reviews, and the new average will be 4.7, so 4.7*(160+x)=704+5x. The solution is 160. Besides, if you want to get the answer really fast, you can see that 4.7 is right in the middle of 4.4 and 5, so you can immediately guess that the number of new 5-star reviews should be equal to the number of current reviews.
First, simplify the radicals
√125=√(5*5*5)=(√5*5)(√5)=5√5
so 3√125=3*5√5=15√5
and √16=4
so
15√(5)-4 is the simplified version
To find equivalent inequalities you have to work the inequality given.
The first step is transpose on of sides to have an expression in one side and zero in the other side:
x - 6 x + 7
--------- ≥ --------
x + 5 x + 3
=>
x - 6 x + 7
--------- - -------- ≥ 0
x + 5 x + 3
=>
(x - 6) (x + 3) - (x + 7) (x + 5)
--------------------------------------- ≥ 0
(x + 5) (x + 3)
=>
x^2 - 3x - 18 - x^2 - 12x - 35
--------------------------------------- ≥ 0
(x + 5) (x + 3)
15x + 53
- ------------------- ≥ 0
(x + 5) (x + 3)
That is an equivalent inequality. Sure you can arrange it to find many other equivalent inequalities. That is why you should include the list of choices. Anyway from this point it should be pretty straigth to arrange the terms until making the equivalent as per the options.
Fidn volume
V=hpir^2
d/2=r
1.4/2=0.7=r
height=3.5
V=3.5*3.14*0.7^2
V=5.3851
1.5 times t=5.3851
divide both sides by 1.5
t=3.59
round
t=4
4 minutes
Answer: C (x, y) ➔ (0.375x, 0.375y)
