This week in Pre calc 11 we have been working on rational expressions. I learned how to tackle word problems with rational expressions this is useful because many of these word problems are problems that you would tackle in the real world. I’m going to be talking about distance, speed and time problems. To get started we need to memorize this formula that can help us solve:  if you want to find speed, you cover speed with your finger and see that distance is on top of time, this means that we need to divide distance over time to figure out speed. The same goes for the rest.

World Problem:  Evan drove 308 km at the same time that Meghan drove 329 km. If Meghan drove on average 6km/h faster than Evan, calculate her average speed and the time taken for the journey. 

step 1. Read the questions carefully and figure out what you are trying to find. We are trying to find Meghan’s speed.

step 2. Make a let statement. This word problem doesn’t tell us the time, it only tells us that Meghan was 6km/h faster. Therefore let x be Evans speed.

step 3. Draw your table and plug in numbers

step 3. time. to find the time, we use our triangle. Distance divided by speed. the only information given about time is that Mgehan and Evan drove in the same time. This indicates that our expressions would equal one another.

step 4. solve the equation.

Step 5. add 6 because meghan was 6km/h faster