Question

There is a heap of 1000 balls uniquely numbered from 1 to 1000. If the last digit of fhe ball is 0,it is put into bucket

Answer 1

Answer:

100 balls in the bucket

Step-by-step explanation:

Total number of balls = 1000

Number of balls with last digit = 0

⇒ It is a multiple of 10s

Find the first number of digits from 1 to 1000 that is a multiple of tens:

First number = 10

Find the last number of digits from 1 to 1000 that is a multiple of tens:

Last number = 1000

Find n:

First number = a1 = 10

Last number = an = 1000

Common Difference = d = 10

an = a1 + (n - 1)d

1000 = 10 + (n - 1)10

1000 = 10 + 10n - 10

1000 = 10n

n = 1000 ÷ 10 = 100

Answer: There are 100 balls that are in the bucket.