46) Which of the following operation is not applicable for making a regular hexagonal nut?

47) For a hole of diameter 8 mm, the reaming allowance should be about

48) A brazed joint is

49) The standard temperature at which measurement shall be taken is

50) Father's age 7 years before was one more than 3 times of his son's age. Father's age after 10 years will be 2 less than 2 times son's age. What is son's present age?