Elementary Math Problem

Question

Juan bought 3 1/3 kg of lizard food. he used 1 1/4kg to feed his lizard and 1.2kg to feed his sisters smaller lizard. How much lizard food does Juan have left his lizard?

Answer 1

3 1/3 kg total

1 1/4 kg to his lizard

1.2 kg to his sister's lizard

1.2 kg = 1 2/10 kg = 1 1/5 kg

3 1/3 kg total

1 1/4 kg to his lizard

1 1/5 kg to his sister's lizard

Find a LCM of 3,4, and 5.

60

3 20/60 kg total

1 15/60 kg to his lizard

1 12/60 kg to his sister's lizard

3 20/60 - 1 15/60 - 1 12/60

(3 20/60 - 1 15/60) = 2 5/60

2 5/60 - 1 12/60 = 1 65/60 - 1 12/60 = 53/60 kg or 0.8833 kg

Answer 2

Let's start by converting 1.2 kg into a fraction of 1 1/5 kg.

Now let's find a common denominator between all 5 numbers: 3 1/3, 1 1/4, 1 1/5,

3 * 4 * 5 = 60 is the LCD for these numbers, so we know the solution is:

3 1/3 - 1 1/4 - 1 1/5 but we must write this with the common denominators:

3 20/60 - 1 15/60 - 1 12/60

Now we can convert all mixed fractions into whole fractions and solve:

(180 + 20)/60 - (60 + 15)/60 - (60 + 12)/60

200/60 - 75/60 - 72/60

(200 - 75 - 72)/60 = 53/60

Juan has 53/60 kg of lizard food for his lizard.