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Lesson 4: Rational number word problems

# Rational number word problem: cab

Budgeting money is one of the most valuable math skills you'll learn. Practice with us as we figure out how much money is left after a cab fare. Created by Sal Khan.

## Want to join the conversation?

• I did this a completely different way. I personally found this video a tad confusing, however I understand there are multiple ways of doing math.
What I did was 5 miles X \$2.50 = 12.5 (now you got the only number you don't know)

Next I just did this: \$20 - \$2.50 (cab fee) - \$12.5 - \$1 (tip) = \$4
• could it also be done like this?
\$20-\$2.50 = \$17.50
\$17.50 - ( \$2.50x5)
= \$5 - \$1
=\$4
• There are many ways in solving a problem. What you just did is one way, and Sal 's is another way. In conclusion both ways are correct if you end up with the same answer!
• I got this question: to take the taxi, it costs \$3.00 plus an additional \$2.00 per mile traveled. you spent exactly \$20 on a taxi, which includes a \$1 tip left.

then it asks me how much miles I have left

I am soo confused
• well, you know the 3 and 1 dollar won't change, so you can take those out, leaving you with 16 dollars, and it is probably asking how many miles you can travel with that money
• Why are there 7 videos in a row? does anyone else have it like this with 7 videos in a row?
• Why are there so many videos on just one topic? i think i get it my the second or third video.
• My answer to this is more simple, or as I believe so:

Things to remember:
- Remember that each mile is \$2.50. Sand is taking 5 miles.
- When you enter the cab, you have to pay \$2.50.
- Sandy left a 1 dollar tip.
- Sandy has 20 dollars.

Now to the equation:
2.50(payment per mile) * 5(miles) = 12.5(she pays for miles) =
12.5 + 2.50(this is for entering cab) = 15 bucks =
15 + 1(the tip Sandy gave) = 16

Now subtract 16 from the total dollars she has.
20 - 16 = 4

Then, Sandy has 4 dollars left.

Thanks,
KocaKola
• i think this is easy but sometimes the rounding is hard for me. i just don't like the rounding at all😐
(1 vote)
• Michael just finished a great meal in a restaurant in Wisconsin. The sales tax in Wisconsin is 5% and it is customary to leave a tip of 15% for the waiter. The tip amount is calculated on the price of the meal before the tax is applied. Sales tax is not calculated on tips.
If Michael left \$18 on the table to cover his meal, tax, and tip, what was the price of his meal before tax and tip?

"Adding 20 percent to an amount is the same as multiplying that amount by 1.20" ---This hint threw me off, I have no idea how to get the decimal 1.20, and it doesn't really tell you why or how. Also, I got it wrong because I did something like this 18 - (18*0.2) = 14.4. The rest of the hints explain it well but that one point I'm not getting.
• let's call P the price of the meal before tax and tip.
Together, the tip and tax are 20% but it's important to remember that the tip and tax are calculated on the price before tax and tip (P). \$18 is the price after tip and tax. Using your method this would be expressed as
``P + (P*0.2)=18P + 0.2P =181.2P = 18 ``

can you see what the hint is trying to tell you?