Hello,
the first step should be to distribue:
-4(3-5x)= -12+20x
Teh resolution may be:
-4(3-5x)>=-6x+9
==>-12+20x>=-6x+9
==>20x+6x>=9+12
==>26x>21
==>x>=21/26
But an other way may be used:
-4(3-5x)>=-6x+9
==>3-5x<= -6x/(-4)+9/(-4)
==>-5x-3/2 x<=-9/4 -3
==>-13/2 x <=-21/4
==>x>= -21/4 *(-2/13)
==>x>=21/(2*13)
==>x>=21/26
Get rid of all common factors.
36/4 = 9
x^9/x^7 = x^2
y^4/y^3 = y
The r% of a quantity x is computed by dividing x in 100 parts, and considering r of such parts. So, the r% of the male is
and similarly, the r% of female is
The number of males decreased by this quantity, so now it is
and the number of female increased by this quantity, so now it is
we know that these two new counts are the same number, so we can build and solve the equality
Subtract 20 and add 0.3r from both sides:
Divide both sides by 0.5 to solve for r:
Let's check the answer
The 20% of 30 is 
, while the 20% of 20 is 4. So, we are stating that 
which is true because both expressions evaluate to 24.
Morgan should first take the 40% off then apply the $15 coupon
Lets say her total was $150.
If you take the 40% off first, you get $90
150 * .6 = 90 (since you are taking off 40% you are still paying the rest of the 60% so you can just save extra steps by multiplying by .6 and not .4)
Now you subtract 15 from that value.
90 - 15 = 75 If Morgan takes the 40% off first and then applies the $15 dollar coupon, she has to pay $75.
If she applies the $15 coupon first, her total before the 40% is $135
150 - 15 = 135
The total will come out to be $81
$135 * .6 = 81
If Morgan takes the discount first before applying the coupon she has to pay less and saves the most money.
