The least number which when divided by 35, 45, 55 leaves the remainder 18, 28, 38 respectively is

35 – 18 = 17

45 – 28 = 17

55 – 38 = 17

i.e., difference between the divisor and corresponding remainder is same.

LCM of 35, 45 and 55 = 3465

∴ Required number = 3465 – 17 = 3448