Question

Lisa is weighing combinations of children's blocks. four blue blocks and five red blocks weigh 32 ounces. one blue block and eight red blocks weigh 35 ounces. what is the combined weight of one red block and one blue block?

Answer 1

4b + 5r = 32
b + 8r = 35.....multiply by -4
----------------
4b + 5r = 32
-4b - 32r = - 140 (result of multiplying by -4)
---------------add
- 27r = - 108
r = -108/-27
r = 4 <== each red block weighs 4 oz

b + 8r = 35
b + 8(4) = 35
b + 32 = 35
b = 35 - 32
b = 3 <=== each blue block weighs 3 oz

so 1 red block + 1 blue block weight (3 + 4) = 7 oz <==

Answer 2

following are calculations of the weight:

Given:

blue =4

red= 5

total weight= 32

and

blue =1

red= 8

total weight= 35

To find:

weight of 1 red and 1 blue=?

Solution:

blue =4

red= 5

total weight= 32

So equation:

$\to 4b + 5r = 32...........................(a)$

similarly

blue =1

red= 8

total weight= 35

So equation:

$\to 1b+8r=35..............(b)$

Solving the equation (b) and putting its value into equation (a):

$\to 1b+8r=35\\\\\to b= 35-8r$

putting the value into equation (a):

$\leq \to 4(35-8r) + 5r = 32\\\\ \to 140 -32r + 5r = 32\\\\ \to -27r = 32-140\\\\\to -27r=-108\\\\\to r=\frac{108}{27}\\\\\to r=4$

Putting the value of r in the equation (a):

$\to 4b + 5(4) = 32\\\\\to 4b + 20 = 32\\\\\to 4b= 32-20\\\\\to 4b=12\\\\\to b=\frac{12}{4}\\\\\to b= 3$

Following are the calculation of the weight of

$\to \text{W=1 red block + 1 blue block }$

       $= 3 + 4\\\\ = 7$

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brainly.com/question/9801213