Question

1+ ( 3+5+7+--+49 )
( a_{n}=49 )
( a=1 )
( a=2 )
( a_{n}=a+(n-1) d )
( 49=1+(n-1) times 2 )
( n-1=frac{48}{2} )
( n=27+1=25 )
( 5 n=frac{25}{2} times(1+49) )
( =frac{25}{2} times 50=25 times 25=(25)^{2} )

# 7.1 + 3+ 5 + 7 + ... + 49 should be equal to (a) 492 (b) 24 (c) 252 (d) None of these 8. 10.9 x V1.6 = ? (a) 0.12 (b) 1.2 (c) 0.75 (d) 12

Solution