Step-by-step explanation: So the map has a scale of 1 cm: 20 km. Next, you look at how far they are apart and see if the scale and the distance on the map are the same measurement. In this case, they are both centimeters so they stay the same. Then, all you do is multiple the real size, 20 km, by
2.5
/1
. Then, 20 x 2.5=50. So the answer is 50 km
If the bacteria is tripling every 10 minutes, that means the "rate of increase" on that period is 200%, so if say the current amount is "c", 200% of "c" is just 2c, so c + 2c is 3c, a tripled amount.