Same pattern as Four numbers — the missing one. New numbers, new story. Try each one on paper, then check the working below — or watch it drawn out, the same way the problem above is.
Question 1
The mean mass of four parcels is 24 kg. Three of the parcels have masses of 19 kg, 26 kg, and 30 kg. Find the mass of the fourth parcel.
Work it out on paper, then check below. ▶ See the working
Question 2
The mean amount of money saved by four pupils in a week is $18.50. Three of them saved $15, $20.50, and $22.50. How much did the fourth pupil save?
Work it out on paper, then check below. ▶ See the working
Question 3
The mean age of four cousins is 12 years. Three of the cousins are 9, 13, and 15 years old. Find the age of the fourth cousin.
Work it out on paper, then check below. ▶ See the working