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# AQA a level maths D1 watch

1. Guys, I'm stuck on this question!!!

A wall is to be built using two types of brick of equal thickness. The wall is to be 3m high, 100m long and the thickness of a single brick. The large type of brick is of height 10cm and length 20cm. The small type of brick is of height 5cm and length 10cm.

A)Ignoring the mortar between bricks, the constraint 4L + S Is greater or equal to 60 000 ensures that there are enough bricks available to construct the wall. Identify the meanings of the variables L and S, and explain why the constraint works

Each large brick needs 0.5 litres of mortar. Each small brick requires 0.25 litres of mortar. There are 10 000 litres if mortar available.

B) write down a constraint on the numbers of each type of brick to ensure that there is sufficient mortar.

Large bricks cost 25p each and small bricks cost 5p each.

C) formulate an LP to find out how many bricks of each type to use to build the wall at minimum cost

D) use a graph to solve your LP.

2. (Original post by Hunkybm)
Guys, I'm stuck on this question!!!

A wall is to be built using two types of brick of equal thickness. The wall is to be 3m high, 100m long and the thickness of a single brick. The large type of brick is of height 10cm and length 20cm. The small type of brick is of height 5cm and length 10cm.

A)Ignoring the mortar between bricks, the constraint 4L + S Is greater or equal to 60 000 ensures that there are enough bricks available to construct the wall. Identify the meanings of the variables L and S, and explain why the constraint works

Each large brick needs 0.5 litres of mortar. Each small brick requires 0.25 litres of mortar. There are 10 000 litres if mortar available.

B) write down a constraint on the numbers of each type of brick to ensure that there is sufficient mortar.

Large bricks cost 25p each and small bricks cost 5p each.

C) formulate an LP to find out how many bricks of each type to use to build the wall at minimum cost

D) use a graph to solve your LP.

A) convert all units into cm. Then work out the volume of the wall and of each brick, notice anything about the volumes compared with that of the 4L + S >/= 60,000

B) You have the amount of mortar for each brick and the amount you have overall, try and construct an inequality looking at how they did it for part a)

C) You have two inequalities, you now need to construct one with to do with the money and just the general equation saying you can't have a negative number of bricks :P Try drawing a table saying what you know about each brick so volume, price and mortar

D) Once you know all this just draw a graph

I've tried to give hints rather than full answers, have a go and if you still can't get it write down what your workings were so I can see where you went wrong
3. (Original post by Munrot07)
A) convert all units into cm. Then work out the volume of the wall and of each brick, notice anything about the volumes compared with that of the 4L + S >/= 60,000

B) You have the amount of mortar for each brick and the amount you have overall, try and construct an inequality looking at how they did it for part a)

C) You have two inequalities, you now need to construct one with to do with the money and just the general equation saying you can't have a negative number of bricks :P Try drawing a table saying what you know about each brick so volume, price and mortar

D) Once you know all this just draw a graph

I've tried to give hints rather than full answers, have a go and if you still can't get it write down what your workings were so I can see where you went wrong
Thank you so much! The teacher didn't collect it in the end so

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