Question

The number of ducks around the lake in a Minnesota decreased by 40% between lastyear and this year. Last year there were 95 ducks around the lake. What is thepopulation this year? Draw either a double number line or a tape diagram to helpillustrate your thinking.

Answer 1

The original population of ducks in the lake was 95.

The population decreased 40% in one year.

To determine the population of this year, you have to calculate how many ducks does 40% represent. To do so, multiply the original amount by 0.4

`95\cdot0.4=38`

This means that in one year the number of ducks was reduced by 38.

Subtract 38 from 95 to determine the actual population

`95-38=57`

The actual population is 57 ducks

You have to draw in the number line the original and the actual populations: