7th term of an arithmetic sequence is 20and its 10 th term is 44.what is 15 th term?
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7th term =a+6d
20=a+6d. ............... 1 equation
10th term=a+9d
44=a+9d. ...............2equation
now solve 1st and 2nd equation
-14=-3d
d=14÷3
put the value in 1st equation
20=a+6×14÷3
20=a+2×14
a=20-28
a=-8
15th term=a+14d
15th =-8+14×14%3
=-8+196%3.
=-8+65.33
=57.33
20=a+6d. ............... 1 equation
10th term=a+9d
44=a+9d. ...............2equation
now solve 1st and 2nd equation
-14=-3d
d=14÷3
put the value in 1st equation
20=a+6×14÷3
20=a+2×14
a=20-28
a=-8
15th term=a+14d
15th =-8+14×14%3
=-8+196%3.
=-8+65.33
=57.33
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