Final answer:
Jean will need to divide the total amount of glue needed, 9/10 ounces, by the amount in each tube, 1/5 ounce, giving us 4.5 or 5 tubes when rounded up since glue comes in entire tubes.
Step-by-step explanation:
The student needs to calculate how many tubes of glue Jean will use to build her model car, knowing that each tube contains 1/5 of an ounce of glue and the total required is 9/10 of an ounce.
To find the number of tubes needed, we set up an expression that divides the total amount required by the amount in each tube. This results in the expression 9/10 ÷ 1/5. To solve this, we multiply by the reciprocal of 1/5, which is 5/1.
The calculation would be: (9/10) × (5/1) = 45/10 = 4.5. Since we cannot have half a tube, Jean will need 5 tubes of glue, as she must purchase whole tubes.