Please solve the word problem. Siti opened a 2-kg packet of flour. She used 4/9 of the flour to make a pizza. Then she used 2/7 of the remaining flour to make cakes. Find the mass of the packet of flour that she had left. Express your answer correct to 2 decimal places.
start 2 kg
then used 4/9, 5/9 left
then used 2/7, 5/7*5/9 = 25/63 left
25/63 = use calculator
To solve this problem, we'll need to find the mass of the flour that Siti had left.
Let's start by finding the amount of flour Siti used to make the pizza. She used 4/9 of the 2-kg packet of flour, so:
Flour used for pizza = (4/9) * 2 kg
= 8/9 kg
Next, we need to find the remaining flour after making the pizza. This can be calculated by subtracting the flour used for the pizza from the total amount of flour:
Remaining flour = Total flour - Flour used for pizza
= 2 kg - (8/9) kg
To subtract fractions with different denominators, we need to find a common denominator. In this case, the common denominator is 9:
Remaining flour = (18/9) - (8/9) kg
= (18 - 8)/9 kg
= 10/9 kg
Now, Siti used 2/7 of the remaining flour to make cakes. Let's calculate how much flour was used for the cakes:
Flour used for cakes = (2/7) * (10/9) kg
= 20/63 kg
Finally, to find the mass of the packet of flour that Siti had left, we subtract the flour used for the cakes from the remaining flour:
Mass of packet left = Remaining flour - Flour used for cakes
= (10/9) kg - (20/63) kg
Again, we need to find a common denominator to subtract the fractions:
Mass of packet left = (70/63) - (20/63) kg
= (70 - 20)/63 kg
= 50/63 kg
To express the final answer correct to 2 decimal places, we can calculate:
Mass of packet left ≈ 0.79 kg
Therefore, Siti had approximately 0.79 kg of the packet of flour left.
To solve this word problem, we need to calculate the mass of the packet of flour that Siti had left.
Let's break down the problem step by step.
Step 1: Calculate the mass used to make a pizza.
Siti used 4/9 of the flour to make a pizza. To find the mass used, we need to multiply this fraction by the total mass of the flour packet.
Mass used for the pizza = (4/9) * 2 kg
Step 2: Calculate the remaining flour after making the pizza.
To find the remaining flour, we need to subtract the mass used for the pizza from the total mass of the flour packet.
Remaining flour after making the pizza = total mass - mass used for the pizza
Step 3: Calculate the mass used to make cakes.
Siti used 2/7 of the remaining flour to make cakes. To find the mass used, we need to multiply this fraction by the remaining flour mass calculated in Step 2.
Mass used for the cakes = (2/7) * (remaining flour mass)
Step 4: Find the remaining flour after making the cakes.
To find the remaining flour after making the cakes, we need to subtract the mass used for the cakes from the remaining flour mass calculated in Step 2.
Remaining flour after making the cakes = remaining flour mass - mass used for the cakes
Now let's calculate the answers:
Step 1: Mass used for the pizza = (4/9) * 2 kg = (8/9) kg ≈ 0.89 kg (rounded to 2 decimal places)
Step 2: Remaining flour after making the pizza = 2 kg - 0.89 kg = 1.11 kg
Step 3: Mass used for the cakes = (2/7) * 1.11 kg ≈ 0.32 kg (rounded to 2 decimal places)
Step 4: Remaining flour after making the cakes = 1.11 kg - 0.32 kg = 0.79 kg
Therefore, the mass of the packet of flour that Siti had left is approximately 0.79 kg.