20% off means it is selling for 80% of the original price ( 100% - 20% =80%)
Divide the sale price by 80% as a decimal:
380/0.80 = 475
The original price was $475
Justify:
Multiply the original price by 20% and subtract:
475 x 0.20 = 95
475-95 = $380 which is the sale price.
In an arithmetic sequence:
Tn=t₁+(n-1)d
t₄=t₁+(4-1)d=t₁+3d
t₅=t₁+(5-1)d=t₁+4d
t₆=t₁+(6-1)d=t₁+5d
t₄+t₅+t₆=(t₁+3d) +(t₁+4d)+(t₁+5d)=3t₁+12d
Therefore:
3t₁+12d=300 (1)
t₁₅=t₁+(15-1)d=t₁+14d
t₁₆=t₁+(16-1)d=t₁+15d
t₁₇=t₁+(17-1)d=t₁+16d
t₁₅+t₁₆+t₁₇=(t₁+14d)+(t₁+15d)+(t₁+16d)=3t₁+45d
Therefore:
3t₁+45d=201 (2)
With the equations (1) and (2) we make an system of equations:
3t₁+12d=300
3t₁+45d=201
we can solve this system of equations by reduction method.
3t₁+12d=300
-(3t₁+45d=201)
-----------------------------
-33d=99 ⇒d=99/-33=-3
3t₁+12d=300
3t₁+12(-3)=300
3t₁-36=300
3t₁=300+36
3t₁=336
t₁=336/3
t₁=112
Threfore:
Tn=112+(n-1)(-3)
Tn=112-3n+3
Tn=115-3n
Now, we calculate T₁₈:
T₁₈=115-3(18)=115-54=61
Answer: T₁₈=61
Answer:
B. Negative
Step-by-step explanation:
We are given that x equals negative and y equals positive.
That means the fraction is negative multiplied by the 7y³ term, which is positive.
Negative times positive is negative, so B is our answer.
Answer:
It will take him 1 hour and 30 minutes. (90 minutes)
Step-by-step explanation:
If he is running 1 mile in 10 minutes and he needs to run 9 miles the just multiply 9 by 10 to get 90 then simplify if you need to to get 1 hour and 30 minutes.
Hope this helped and have a great rest of your day.
A) -9
-7(x+9)=9(x-5)-14x
-7x-63=9x-45-14x
-45 -45
-7x-18=9x-14x
+7x +7x
-18=9x+7x-14x
-18=2x
(-18)/2=(2x)/2
-9=x
