Problem 7.1 How Far?
How far will a train travelling at 72 km/h go in 1 second?
Problem 7.2 A Car
A car travelling at a speed of 36 km/h covers a distance of 1000 cm in
1 second. How many centimetres per second is covered by a car
travelling at a speed of 54 km/h?
Problem 7.3 A Long Chain
It costs $2 to open a link and $3 to weld it closed. A lady wants
to join the six pieces shown above into one long chain. What is the
maximum cost?
Problem 7.4 Brine Solution
We have 1000 mL of a 20% solution of a brine. How much water
should be added to make it a 10% solution?
Problem 7.5 A Record
A table tennis team has won 5 of its 7 games. How many of the 8
remaining games will the team need to win to have a season record of
winning 80% of its games?
Problem 7.6 A Car Tyre
A car tyre has two punctures. By itself, the first puncture would
make the tyre flat in 15 minutes. By itself, the second puncture
would make the tyre flat in 12 minutes. How long will it take for
both punctures together to make the tyre flat (assuming that the air leaks
out at a constant rate)? |
