Answer:
11m + 4n
Step-by-step explanation:
when two numbers with the same variable are added together or subtracted the result is just the numbers added or subtracted. So you can add 6m and 5m to get 11m. and you can subtract 3n from 7n to get 4n
11m + 4n
20 and 28 can be divided by 4, so just take the 4 out so the answer should be 4(5x - 7)
(5*7) - (5*4) = 35 - 20 = 15
you "distribute" the 5 but multiplying it to both numbers in the parentheses, and doing the subtraction.
The sample space (list of outcomes) is:
DFNR; DFRN; DRFN; DRNF; DNFR; DNRF;
NFDR; NFRD; NRFD; NRDF; NDRF; NDFR;
RFDN; RFND; RNFD; RNDF; RDFN; RDNF;
FRDN; FRND; FNRD; FNDR; FDRN; FDNR
P(Dave beside Natalie) = 1/2
P(B,G,B,G or G,B,G,B) = 1/3
P(boys in the middle) = 1/6
P(Frida beside Natalie) = 1/2
P(Robbie between Frida & Natalie) = 1/6
P(Natalie between Dave & Robbie) = 1/6
Explanation
Letting D=Dave, R=Robbie, N=Natalie, and F=Frida you get the list of possibilites above.
For P(Dave beside Natalie), look for DN or ND. This appears 12 times out of the 24 possibilities above; 12/24 = 1/2.
For P(B,G,B,G or G,B,G,B), we have the possibilities DFRN, DNRF, RFDN, RNDF, FRND, FDNR, NDFR, NRFD. There are 8 possibilites out of 24; 8/24 = 1/3.
For P(Frida beside Natalie), look for NF or FN. This appears 12 times out of the 24 possibilities; 12/24 = 1/2.
For Robbie between Frida and Natalie, look for FRN or NRF. This appears 4 times out of 24; 4/24 = 1/6.
For Natalie between Robbie and Dave, look for RND or DNR. This appears 4 times out of 24; 4/24 = 1/6.
