Question

{1,2,3,...75,76,77,78}

Answer 1

Answer:

32

Step-by-step explanation:

even numbers are 2,4,6,...,78

it is an A.P.

first term a=2

c.d. d=4-2=2

an=a+(n-1)d

78=2+(n-1)2

76=(n-1)2

n-1=76/2=38

n=38+1=39

now we take multiples of 10

10,20,30,...,70

70=10+(n-1)10

60=(n-1)10

n-1=60/10=6

n=6+1=7

so reqd. number of numbers=39-7=32