Question 21 The reciprocal of −38×(−713) is (a) 10421 (b) −10421 (c) 21104 (d) −21104
Given number is −38×(−713) The product of −38×(−713)=21104 Hence, the multiplication inverse of 21104 is 10421 i.e option (a).
Sum of the series S=1+12(1+2)+13(1+2+3)+14(1+2+3+4)+ .....upto 19 terms is