Question

........./5=quotient 64 and reminder 1

Answer 1

(dividend-remainder)/divisior = quotient
( x -1)/5 = 64
x - 1 = 64 x 5
x - 1 = 320
x = 320 + 1 
x = 321

Answer 2

Dividend=divisor*quotient+remainder
dividend=5*64+1
dividend=321
therefore,
321/5=quotient 64 and remainder 1......