A grocer wants to mix two kinds of coffee. One kinds sells for $1.15 per pound, the other sells for $1.40 per pound. He wants to mix a total of 30 pounds and sell it for $1.35 per pound. How many pounds of each kind should he use in the new mix

Step-by-step explanation:

Let the amounts (weights) of the $1.15 mix and the $1.40 mix be c and d.

Then c + d = 30 lb.  We can solve this for c, obtaining d = 30 - c.  

The cost equation is ($1.15/lb)c + ($1.40/lb)d = ($1.35/lb)(30 lb)

Substituting 30 - c for d, we get:

($1.15/lb)c + ($1.40/lb)(30 - c) = ($1.35/lb)(30 lb).  Solve this for c:

1.15c + 42.00 - 1.40c = 40.5.

Then -0.25c = 40.5 - 42.0, or -1.5.

Finally, -0.25c = -1.50.  This yields c = 6.

If c = 6 lb, then (30 - 6) lb = d = 24 lb.

Need 24 lb of the $1.15/lb kind and 6 lb of the $1.40/lb kind.

answer:

total cost for tiles and paints is $924.  

step-by-step explanation:

we have been given that a community hall is in the shape of a cuboid. the hall is 40m long 15m high and 3m wide.

the paint will be required for 4 walls and ceiling.

let us find area of walls and ceiling.

therefore, the area of walls and ceiling is 1410 square meters.

given: cost for 10 litre of paint is $10 and 10 litre paint covers 25 square meter. therefore,

therefore, the total painting cost is $564.

tiles will be required for floor. let us find the area of floor.

given: 1m squared floor tiles costs $3. so,

therefore, the total tiles cost is $360.

now let us find combined total cost of tiles and paint.

therefore, the combined total cost of tiles and paint is $924.