The number of pencils Mary has is:

       9 x 5 = 45(pencils)

The number of pencils John and Mary have is:

       45 + 16 = 61(pencils)

                     Answer: 61 pencils

a) Assume that the square number 16 = 4² is equal to \(\dfrac{n}{3}\), so n = 48

b) Assume that the cubic number 27 = 3³ is equal to​\(\dfrac{n}{5}\), so n = 135

If a is odd, then a³ and a² are also odd, so a³ + a² + 1 is odd

If a is even, then a and a² are also even, so a³ + a² + 1 is odd

So a³ + a² + 1 is always odd with any integer a.

The odd number between the six remaining numbers is:

1337 : 7 = 191

So 7 consecutive numbers are 185 ; 187 ; 189 ; 191 ; 193 ; 195 ; 197

Tom : 20 candies

Tony : 80 candies