Answer: 3/16
EXPLANATION
Given,
1/4 of the tomato plants are cherry tomato plants
Since 3/4 of plants in Marlene’s garden are tomato plants.
Then 1/4 of 3/4 plants in Marlene’s garden are cherry tomato plants
1/4 of 3/4 = 1/4 x 3/4
= 3/16
Therefore, 3/16 of all the plants in Marlene's garden are cherry tomato plants