Answer:
95 students out of 125 students would be expected to have stleast one sibling
If he types 40 words a minute, he can type 2000 words in 50 minutes you can solve this by doing 40*50 the number of hours would be less than one
The series in the form of arithmetic progression
The notation of A.P is a, a+d, a+2d.....
The summation notation is â‘
In this series a=3, d=7
Then the summation of A.P is â‘ = n/2(2a+(n-1)d)
=18/2(2*3+ (18-1)7)
= 9(6+17(7))
=9(6+119)
=9(125)
= 1125
Hence the total number of beads is 1125
