Answer:
Step-by-step explanation:
The terms of this sum make the arithmetic sequence.
The fomula of a sum of <em>n</em> terms of an arithmetic sequence:
![S_n=\dfrac{[2a_1+(n-1)d]\cdot n}{2}](https://tex.z-dn.net/?f=S_n%3D%5Cdfrac%7B%5B2a_1%2B%28n-1%29d%5D%5Ccdot%20n%7D%7B2%7D)
We have
Substitute:
![S_{50}=\dfrac{[2\cdot2+(50-1)\cdot15]\cdot50}{2}=(4+49\cdot15)\cdot25=(4+735)\cdot25\\\\=739\cdot25=18,475](https://tex.z-dn.net/?f=S_%7B50%7D%3D%5Cdfrac%7B%5B2%5Ccdot2%2B%2850-1%29%5Ccdot15%5D%5Ccdot50%7D%7B2%7D%3D%284%2B49%5Ccdot15%29%5Ccdot25%3D%284%2B735%29%5Ccdot25%5C%5C%5C%5C%3D739%5Ccdot25%3D18%2C475)
Answer:the length of the shorter string= 36cm
Step-by-step explanation:
Let us assume the lengths are 2x and 7x since thery are in the ratio of 2 :7
Such that Length of the shorter string = 2x
and the longer string = 7x so that the difference in Length which is 90cm can be expressed as
7x- 2x= 90
5x= 90
x 90/5
x= 18
shorter string = 2 x = 2x 18= 36cm
Longer strring = 7x 18=126cm
Answer:
I think the equation is 7l +5=60
Step-by-step explanation:
Step-by-step explanation:
hope this helps you thank you
