Answer:
38
Step-by-step explanation:
We can express the 8th term as x and the 12th term as y.
This would mean that 8x=12y
Because the common difference between terms is -2 and term 8 and term 12 are 4 terms apart, this means that the 12th term is 8 less than the 8th term, so x-8=y
Now we can use this to substitute y with x in the first equation. This would give us:
8x=12(x-8)
Which we can expand and solve:
8x=12x-96
-4x=-96
Therefore x=24
This means the 8th term is 24 and the 12th term is 16 (24-8).
To test if this is correct we can do:
8x24=12x16
Which indeed are equal, both sides multiply to 192.
Now that we have our 8th term, we can find the 1st term, which is 7 terms away, therefore we just add 14 to the 8th term 24. (7x2=14)
24+14=38.
The first term is 38.
Hope this helped!
To calculate the speed of the 70 teeth countershaft drive gear, evaluate the surface teeth per minute (STM) of each gear. STM = Speed x number of teeth, which is equivalent for both gears. Thus, 45 teeth * 450 r.p.m. = 70 teeth * 'x' r.p.m. is the governing equation. Rearranging the equation to calculate 'x' as the 70 teeth gear's speed, the answer is 289.3 r.p.m.
Answer:
No multiplying both quantities in the ratio 60 : 36 by 1 would not give the answer .
But multiplying both quantities in the ratio 60 : 36 by 1/6 would solve it.
Step-by-step explanation:
Multiplying any number or ratio by 1 gives the same answer no matter what the expression or how much bigger the number is.This will not give the solution .
If it is multiplied with a fraction like 1/6 that would give the correct answer.
Multiplying it with 1/6 reduces the ratio and gives a better estimate.
A:B
60:36
60*1/6: 36*1/6
10: 6
Meaning that for a total of 16 there are 10 of category A and 6 of category B.
But if we do the same procedure with the answer is same which does not solve the question.
A:B
60:36
60*1: 36*1
60: 36