What is the value of the question mark?
What is the value of "?"
a)21
b)23
c)14
d)18
A box of biscuits
A box of biscuits contains 36 biscuits. 20 biscuits have foil wrappers. 15 are chocolate biscuits with foil wrappers. If 9 are not chocolate and do not have a foil wrapper, then how many chocolate biscuits are there?
The star = r
ReplyDeleteThe circle = g
The square = b
The triangle = y
So if we just look at r and y the we'll see that:
2r + y = 14
r + 2y = 19
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and if you add these two equations together you will get => 3r + 3y = 33
if 3r + 3y = 33 then r + y = 11 and 2r + y = 14 then r = 3.
Also if 2r + y = 14 and r = 3 then it would be 2 * 3 + y = 14 so 6 + y = 14 and y = 8.
Now lets look at g and r:
So we know that 2g + r = 15 and r = 3 so we can substitute that in:
2g + 3 = 15
2g = 15 - 3
2g = 12
g = 6
Now let us look at the equation g + b + y = 19:
We already know that g = 6 and y = 8, so we can substitute that in:
6 + b + 8 = 19
14 + b = 19
b = 19 - 14
b = 5
Finally, lets look at the question mark equation:
g + b + r = ?
We already know g, b and r so we can substitute those in:
6 + 5 + 3 = ?
? = 14
so we get our answer
? = 14
well done riti
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