Miss Mills is making jam to sell at the school fair. The cost of one kilogram of strawberries is seven pounds 50. The cost of one kilogram of sugar is 79 p. The cost of 10 glass jars is six pounds 90. She uses 12 kilograms of strawberries and 10 kilograms of sugar to make 20 jars full of jam. Calculate the cost to make 20 jars full of jam.
Miss Mills has three costs: the cost of strawberries, the cost of sugar, and the cost of the glass jars. We know that strawberries cost seven pounds 50 per kilogram. And Miss Mills uses 12 kilograms of strawberries. To work out the cost of 12 kilograms of strawberries, we need to multiply 12 by seven pounds 50. 10 times seven pounds 50 is 75 pounds. And two times seven pounds 50 is 15 pounds. 75 pounds plus 15 pounds equals 90 pounds. So the cost of the strawberries is 90 pounds.
Now we need to work out the total cost of the sugar Miss Mills used. We know that one kilogram of sugar is 79 p. And the question tells us that Miss Mills used 10 kilograms of sugar. 79 p multiplied by 10 equals 790 pence. We can also write this as seven pounds 90.
The final cost for Miss Mills is the cost of the glass jars. We know that 10 glass jars costs six pounds 90. And the question tells us that Miss Mills needs 20 jars. So to find the cost of 20 jars, we need to double the amount it costs for 10 jars. Double six pounds is 12 pounds. And 90 pence times two is one pounds 80. 12 and one pound 80 equals 13 pounds 80. 12 pounds plus one pound 80 equals 13 pounds 80.
Now that we found the cost of the strawberries, the sugar, and the jars, we can add these three amounts together to give us the total amount of Miss Mills costs. zero plus zero plus zero equals zero. Nine plus eight is 17. We can write the seven and carry the one. Seven plus three is 10 plus the one we carried, which makes 11. Again, we can write the one and we need to carry the other one. Nine plus one is 10, plus the one we carried, again, makes 11. So the total cost for Miss Mills to make 20 jars of jam is 111 pounds and 70 pence.
We calculated the cost of the strawberries, the cost of the sugar, the cost of the jars, and then added these three amounts together to give us our total of 111 pounds 70.