an arithmetic series has first term 160 and common difference d . the sum of the first 25 terms of the series 3500 . find the co
1 answer:
Answer:
d = -
Step-by-step explanation:
The sum to n terms of an arithmetic series is
=
[ 2a₁ + (n - 1)d ]
where a₁ is the first term and d the common difference
Here a₁ = 160, n = 25 and = 3500 , thus
[ (2 × 160) + 24d ] = 3500, that is
12.5(320 + 24d) = 3500 ( divide both sides by 12.5 )
320 + 24d = 280 ( subtract 320 from both sides )
24d = - 40 ( divide both sides by 24 )
d = - = -
You might be interested in
Answer: It will take 4 seconds for the rock to hit the water.
Step-by-step explanation:
Given : Benjamin threw a rock straight up from a cliff that was 48 ft above the water.
If the height of the rock h, in feet, after t seconds is given by the equation
To find : Time taken for the rock to hit the water.
When rock hit the water height becomes zero , i.e. put h = 0 , we get
Divide equation by 2 , we get
The Laue of x for ax²+bx+c =0 is
So ,
Since t cannot be negative , so t= 4
Hence, it will take 4 seconds for the rock to hit the water.