Dinosaur algebra

This task is about using algebraic equations.

Question

a)  A triceratops weighed four times as much as a stegosaurus. Together they weighed 15 tonnes.
     Here is an equation describing their total weight.
x + 4x = 15
  i) What does the x in the equation stand for?

    • The weight of the triceratops.

    • The weight of the stegosaurus.

    • The number of dinosaurs.

    • The total weight of the two dinosaurs.

    • The difference in weight between the two dinosaurs.

Question

  ii)  What is the weight of the stegosaurus?

    • 1 tonne

    • 3 tonnes

    • 4 tonnes

    • 12 tonnes

    • 15 tonnes

Question

A brontosaurus weighed 3 times as much as a triceratops. Together they weighed 48 tonnes.
The equation shows their total weight.
y +   y = 48
To complete the equation correctly, what number should be in the box above?

    • 1

    • 2

    • 3

    • 4

    • 8