How many minutes would it take to plate out 103 g of solid nickel from a Ni^2+ solution with a current of 2.75 amperes? 

you know one mole of Cu2+ takes 2 moles of electrons
Ni^2+ + 2 e- ---->Ni(s)
we will use
I= Q/ time
time = I*Q
I is given so your aim is to get charge
and 1 mole of electrons = 96500C (charge )
Convert 103 g Ni... moles of Ni ...moles of electrons ....Charge ...Time
so 103 g Ni X 1mole Ni/58.69 g X 2moles of electrons/one mole of Ni X 96500 C /1mole of electrons .... convert this into time