Hi, I am facing problem in Arithmetic session 4 in 1 month plan where we find sum of nos in an interval.
when GreMat took example to find sum of multiples of 4 between 12 - 108, the formula used is total no of multiples * median
here total no of multiples is 25 , and median is 60 ( using his method that 12th no will be median so 12*4 = 48 and add it to 1st no i.e is 12. Therefore, 12+48=60 (mean or median)
But , when he takes another example of finding sum of multiples of 5 between [15----150]
I am unable to find the median using same method as above.
no of multiples is 28
now to find median, 28 is even so 14th and 15th nos will be median
to find 14th no. - (14*5=70, 15+70 =85)
to find 15th no.- 90
median - (85+90)/2 = 87.5
Acc to him it should be 82.5 ( he used a different method) Please can someone help me where am I going wrong?