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:
150 = x
Step-by-step explanation:
We can use a ratio to solve
100 batches x batches
------------------- = ---------------------
8 hours 12 hours
Using cross products
100 * 12 = 8x
1200 = 8x
Divide by 8
1200/8 = 8x/8
150 = x
68 because I found out on internet
Answer:
6
Step-by-step explanation:
Answer:
a) Shawn's error was that he Multiplied 15 by 2x only. He didn't Multiply 15 by 7
b) The difference, in square feet, between the actual area of Shawn’s garden and the area found using his expression is given as
98 square feet
Step-by-step explanation:
The area in, square feet, of Shawn’s garden is found be calculating 15(2x + 7). Shawn incorrectly says the area can also be found using the expression 30x + 7.
The correct area =
15(2x + 7).
= 30x + 105 square feet
The error in Shawn’s expression is
= 15(2x + 7)
= 30x + 7 square feet
Shawn's error was that he Multiplied 15 by 2x only. He didn't Multiply 15 by 7
The difference, in square feet, between the actual area of Shawn’s garden and the area found using his expression is given as
30x + 105 square feet - 30x + 7 square feet
= 30x + 105 - (30x + 7)
= 30x - 30x + 105 - 7
= 98 square feet
