Answer: 35 days
Step-by-step explanation:
We have that 2/7 of a jar are use per day to feed the gecko. If she has 10 jars, what we need to do is divide 10 days by 2/7 per day, and we will find the number of days that she can feed her gecko.
-Divide 10 by 2/7:
10 ÷ 2/7
this is equal to the following:

we multiply 10 by the denominator 7 and divide by 2.
solving the operations:

How many days can she feed her gecko with this food ? 35