If P,Q and R are integers satisfying the equations p+q = 12, q+r= 24, P+R=24 then what is their product ? (p*q*r= ?)
Six answers:
2013-12-27 15:59:49 UTC
(6)(6)(18) = ...
llaffer
2013-12-28 00:05:48 UTC
I'll take the first two equations and set them to be q equal to everything else.
p + q = 12
q = 12 - p
q + r = 24
q = 24 - r
Now that I have two equations equal to q, the other halves must also be equal to each other.
12 - p = 24 - r
that and the third equation :
p + r = 24
makes a system of two equations and two unknowns. set the "second" to p in terms of r and substitute it into the "first", then solve for r.
p = 24 - r
12 - p = 24 - r
12 - (24 - r) = 24 - r
12 - 24 + r = 24 - r
-12 + r = 24 - r
2r = 36
r = 18
Now we have r, we can solve for q and p by plugging the value of r into the second and third of the original equations.
q + r = 24
q + 18 = 24
q = 6
p + r = 24
p + 18 = 24
p = 6
Now that we know what p, q, and r are ...
pqr = 6(6)(18) = 648
grunfeld
2013-12-28 00:01:47 UTC
12 + 24 - 24 = 12
2q = 12
q = 6
p = 6
r = 18
pqr = 18 * 36 = 648
ranjankar
2013-12-28 04:24:36 UTC
q + r = 24
p + q = 12
SUBTRACT
r - p = 12
p+r = 24
2r = 36
r = 18
p = 6
q = 6
pqr = 6*6*18 = 648 ANSWER
?
2013-12-28 00:02:36 UTC
p+q = 12
p-q = 0
p = 6
q = 6
r = 18
pqr = 648
Ian
2013-12-28 00:22:27 UTC
I am assuming that the system of equations is
pq = 12
qr = 18
pr = 24.
Multiplying the three equations gives
(pqr)^2 = 12*18*24 = 12*36*12 = (12*6)^2 = 72^2.
Therefore, pqr = +-72.
(Note that for any solution (p1, q1, r1) of the system, (-p1, -q1, -r1) will also be a solution; note that p1*q1*r1 is the negative of (-p1)(-q1)(-r1), so pqr could have either sign.)
May Jesus richly bless you today!
ⓘ
This content was originally posted on Y! Answers, a Q&A website that shut down in 2021.