self Maths Puzzle

A group of 630 children is arranged in rows for a group photograph session. Each row contains three fewer children than the row in front of it. What number of rows is not possible

Read Solution (Total 1)

Let the no. of students in front row be x.
So, the no. of students in next rows be x–3,x−6,x–9 ... so on

If n i.e. no. of rows be then no. of students (n=3)
x+(x–3)+(x–6)=630
3x=639
x = 213
So possible,
Similarly for n = 4
x+(x–3)+(x–6)+(x−9)=630
4x–18=630
x=162

If n = 5
(4x–18)+(x−12)=630
5x–30=630
x=120
Again possible.

If n = 6
(5x−30)+(x−15)=630
6x−45=630
6x=675

x is not Integer
Hence n can not be 6
10 years agoHelpfull: Yes(4) No(0)

self Other Question

There are 2 mean, 3 women and 1 child in Pradeep’s family and 1 man, 1 woman and 2 children in Prabhat’s family. The recommended calorie requirement is- Men: 240, Women: 1990, Children: 1800 and for proteins is: Men: 55 gm, Woman: 45 gm, children: 33 gm. Calculate the total requirement of calories and proteins for each of the two families
In a certain water body, 50 fish were caught, tagged and released to the same water body. A few days later, 50 fish were caught again, of which 2 were found to have been tagged on previous occasion. If the percent of tagged fish in the second catch approximates the percent of tagged fish in water body, what is the approximate number of fish in the water body?