Find four numbers in A.P , whose sum is 50 and in which the greatest number is 4 times the least .

Let the AP be .. a ,a +d , a+2d , a+3d.

Sum of AP = 50

therefore , a + a +d + a+2d + a+3d. = 50

=> 4a + 6d = 50

2a + 3d = 25.................(1)

Also given : the greatest no. is 4 times the least.

4(a) = a+3d

4a-a = 3d

a=d

putting a = d in (1) , we get

5d = 25

d=5

a=5 , as d=a

First four terms are : 5 , 10 ,15 , 20.

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Let the AP be .. a ,a +d , a+2d , a+3d.
Sum of AP = 50
therefore , a + a +d + a+2d + a+3d. = 50
=> 4a + 6d = 50
2a + 3d = 25.................(1)
Also given : the greatest no. is 4 times the least.
4(a) = a+3d
4a-a = 3d
a=d
putting a = d in (1) , we get
5d = 25
d=5
a=5 , as d=a
First four terms are : 5 , 10 ,15 , 20.
 
 
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