4. Mary (denote as M) = 16
Her brother (B) =16/4=4
Hence her brother is (M-B) is 12 years younger than her.
"How old will Mary be when she is twice as old as her brother?"
From the difference we worked out above you should be able to see that 24 is the only possible age Mary will be when she is twice as old as her brother.
Okay, fairly easy "spot the pattern" question.
It may be tricky if you haven't studied sequences/series but hopefully you should be able to see that the sequence is simply "add one and double" Ie, 2, 2+1=3, 3*2=6, 6+1=7, EIGHT, 7*2=14, 14+1=15, 15*2=20
We can see that eight is the odd one out, sorry if that got confusing, I tried to make it accessible and held back from introducing notation you won't be familiar with.
This can get confusing, so sub in something your more used to:
"If all bees are insects and all insects are animals, then all bees are definitely animals?" Obviously true.
Another simple sequence question. Simply double the number before so
1, (1*2=2) , 5 , (5*2=10) , 13 , (13*2=26), 29 , (29*2=/=48)
So we can see that 48 is the odd one out.
This one is very easy if you know your times tables!
25 = Square
24 = Non-square
400 = Square
300 = Non-square
144 = Square
145 = Non-square
From the list we can see that 1600 is the only square number so "he likes that one"
Wasn't entirely sure because of the ambiguity, but I think it's 25.
Again, very simple.
1^3=1, 2^3=8, 3^3=27,
4^3=64, 5^3=125, 6^3=216
Hence ?=64
This one is all about seeing the pattern. Think of the thing as being 3d, you flip it and switch one of the lines to the top. Repeat, etc. That was my interpretation and I was almost certain that
is the answer.