Ask your own question, for FREE!
Mathematics 47 Online
OpenStudy (anonymous):

Determine whether the statement is true or false. If false, provide a counterexample. a) If a natural number is divisible by 7, then it must also be divisible by 21. b) If a natural number is divisible by 7 and 5, then it must also be divisible by 35.

OpenStudy (anonymous):

A false, for example 14 B true

OpenStudy (anonymous):

why

OpenStudy (anonymous):

for A I have given a counterexample for B if a number is divisible of 7 and 5 than that number looks like this: 7*5*x =35*x so 35 is also a factor of that number

OpenStudy (anonymous):

Or for A you can see that 21 is \(7\times 3\) In order for a number to be divisible by 7 it must have 7 as a factor, but to be divisible by 21 it must have 7, and 3 as factors. So any multiple of 7 which has no factor of 3 will not be divisible by 21.

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Latest Questions
kamariana: I need help with math.
1 hour ago 2 Replies 0 Medals
addison123456: a poem about love and loss and growth
1 hour ago 2 Replies 1 Medal
gelphielvr: Which vein do you use when drawing blood from a patient?
1 hour ago 2 Replies 0 Medals
thereneelg: What Education is required to be a Ballet Dancer?
1 day ago 2 Replies 0 Medals
layababyy1235: help please cs ionk
1 day ago 8 Replies 0 Medals
cullenn: "Actions Speak Louder Than Words" About: My cat, Boba
1 day ago 10 Replies 2 Medals
cullenn: "Actions Speak Louder Than Words" About: My cat, Boba
1 day ago 6 Replies 0 Medals
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!