Final answer:
Shelly used a total of 2.42 kg of plant food and has 3.08 kg left. She will need 3.5 kg to feed her strawberry plants two more times, so she does not have enough plant food left.
Step-by-step explanation:
To calculate the total amount of plant food used by Shelly, we need to add the quantities she used for the strawberry and tomato plants. Shelly used 1³/⁴ kg for her strawberries and 2/3 kg for her tomatoes. To find the total amount used, we add these two amounts together:
1³/⁴ kg + 2/3 kg = 1.75 kg + 0.67 kg = 2.42 kg
Shelly originally had 5½ kg of plant food. After using 2.42 kg, she has:
5.5 kg - 2.42 kg = 3.08 kg of plant food left.
To determine if Shelly has enough plant food to feed her strawberry plants two more times, we multiply the amount she uses each time by 2:
1.75 kg x 2 = 3.5 kg
Shelly has 3.08 kg left but needs 3.5 kg, so she does not have enough plant food to feed her strawberries two more times.