An ant moves 18 millimeters every 5 seconds
a beetle moves 8 inches every 3 seconds
the garden is 13 yards long (or it could be 13 inches, i kinda forgot)

1. who crosses the garden first?
2. how long will it take the 2nd insect to cross the garden?

Step-by-step explanation:

First we need to find their rate of speed.

r = d / t

For ant,

Convert millimeters to inches.

1 inch = 25.4 mm

18 mm = 0.7 inch

r = 0.7 / 5

r = 0.14 inches per second

For beetle,

r = 8 / 3

r = 2.7 inches per second

From the rates, you can tell that the beetle crosses the Garden first.

To know how long it takes for the ant to cross is by dividing the length by the rate.

1 yard = 36 inches

13 yards = 468 inches

468 ÷ 0.14 = 668.5 ≈ 669 seconds

In terms of minutes:

11 minutes and 15 seconds

The ant would cross the garden in 11 minutes and 15 seconds (or 669 seconds up to you).