Test scores

Ivan, Tibor and Alex sat a test and achieved 85%, 90% and 95% respectively. Tibor scored just one more mark than Ivan. How many marks did Alex get?
Age
14 to 16
Challenge level
filled star empty star empty star
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

Problem



Ivan, Tibor and Alex sat a test and achieved $85\%$, $90\%$ and $95\%$ respectively. Tibor scored just one more mark than Ivan.

How many marks did Alex get?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.