Question

find the sum of all multiples of 5 lie between 1 and 100​

Answer 1

Answer:

Step-by-step explanation:

there are 19 terms in the sequence

hence sum = s19 =  19/2 [2(5) + (19-1)5]

                             = 19/2 [ 10+ 90]

                             = 19/2 [100]

                              = 19 * 50

                             =   950