give solution

Question

53% of the weight of a concrete slab is cement while the rest is stone ad sand .If there is 20kg 160 gram more cement than stone and sand in the concrete slab, how much does the slab weigh?

Answer 1

Let x = weight of the slab (in kg)

 

Then, 0.53x = weight (in kg) of cement portion

 

         0.53x - 20.16 = weight (in kg) of the stone and sand

 

So, 0.53x + (0.53x - 20.16) = x

 

                                0.06x = 20.16

 

                                      x = 336 kg

 

Answer 2

Lauren H. | Experienced High School Chemistry Teacher
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C(cement) = .53 ( C + S)

C + S is the entire weight of the substance

C - 20160g = S

20160 g is the sum of 20 kg and 160 g

Substitute:

C = .53( C + C - 20160)

Solve for C:

C = .53( 2C - 20160) = 1.06 C - 10684.8

10684.8 = .06 C

Divide to find C

C = 178080, S = 157920 (by subtraction)