Answer:
200 cm (or 2 meters) or 80% of the original 250 cm is left. let me know if you have any questions.
Step-by-step explanation:
I'm not sure if that's asking for an exact amount or percent, so I will do both.
The trick either way is to match units. we have meters and centimeters. You could make either one match the other. so 2.5 m is 250 cm and 50 cm is .5 m.
You do have to know how many centimeters is in a meter, but once you know that you can set up unit conversions, which are super simple.
there are 100 cm in a m. a unit conversion is basically a fraction that cancels out units. starting with 2.5 m we want to cancel out m so the fraction we use has the m part in the denominator. so 2.5m * (100 cm)/(1 m). (100 cm)/(1 m) is the unit conversion, and just like variables the m in the denominator cancles out the m in the starting value so it turns into 2.5 * 100 cm/1 = 250 cm.
similarly to go from 50 cm to meters you make the unit conversion have cm in the denominator. so 50 cm * (1 m)/(100 cm) = .5 m. again, the cm int he denominator cancels out the cm in the unit being multiplied. Let me knwo if this is still not clear.
Anyway, now we have the numbers we need. let's make them all cm, I think using the smallest unit is usually easiest. so that's 250 cm total and 50 cm used.
In pure numbers, that means 200 cm is left (which is 2 meters) after 50 cm gets used.
percents is a little trickier. if 250 is 100% then 50 is 20%, which you can get by doing 50/250. if you do not know, a fraction a/b gives you the percent a is of b. Or rather it gives you a decimal, and if you multiply it by 100 it gives you the percent.
anyway, if 20% is used then 80% is left. if you did 200/250 you would get that.
