SOLUTION: The ratio of students who ride the bus to the students who do not ride the bus is 7 to 3. If 490 students ride the bus, how many students do not ride the bus?

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: The ratio of students who ride the bus to the students who do not ride the bus is 7 to 3. If 490 students ride the bus, how many students do not ride the bus?      Log On


   



Question 342862: The ratio of students who ride the bus to the students who do not ride the bus is 7 to 3. If 490 students ride the bus, how many students do not ride the bus?
Found 2 solutions by stanbon, MathTherapy:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The ratio of students who ride the bus to the students who do not ride the bus is 7 to 3. If 490 students ride the bus, how many students do not ride the bus?
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Note: 7 to 3 is the same as 7x to 3x where 7x is # who do not ride and
bus and 3x is # who do ride the bus.
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Equation:
7x + 3x = 490
10x = 490
x = 49
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# who do not ride = 7x = 7*49 = 343
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Cheers,
Stan H.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
The ratio of students who ride the bus to the students who do not ride the bus is 7 to 3. If 490 students ride the bus, how many students do not ride the bus?

Since the ratio of riders to non-riders is 7:3, then 7%2F10 are riders and 3%2F10 are non-riders

Using N for non-riders, and since there are 490 riders, or 7%2F10 of total riders, and we need to know what number represents non-riders, or 3%2F10 of total riders, we can say that:

%287%2F10%29%2F%283%2F10%29+=+490%2FN

Cross-multiplying, we get: %287N%2F10%29+=+147

Cross-multiplying again, we get: 7N = 1,470

N, or non-riders = 1470%2F7 or highlight_green%28210%29 students.

METHOD II
We could have also done it the shortcut way by noticing that the riders' ratio of 7 was multiplied by 70 to get the total amount of riders, 490 (7 * 70).

Therefore, we can also multiply the non-rider ratio of 3 by 70 to get highlight_green%28210%29 (3 * 70), or simply put:
highlight_green%28%287%2A70%29%2F%283%2A70%29+=+490%2F210%29