document.write( "Question 983047: Ann goes swimming regularly. She wants to improve her fitness, so she decides to swim 10 lengths in the first session and increase the number of lengths she swims by 2 every session. When she reaches 50 lengths in a session, she will not increase the number any further. After how many sessions does Ann swim 50 lengths for the first time? \n" ); document.write( "

Algebra.Com's Answer #603939 by josmiceli(19441) $\"\"$ $\"About$

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1st session:
\n" ); document.write( " $\"+10+\"$ lengths
\n" ); document.write( "2nd session:
\n" ); document.write( " $\"+10+%2B+2+\"$
\n" ); document.write( "3rd session:
\n" ); document.write( " $\"+10+%2B+4+\"$
\n" ); document.write( "4th session:
\n" ); document.write( " $\"+10+%2B+6+\"$
\n" ); document.write( "--------------
\n" ); document.write( "Let $\"+n+\"$ = the number of the session
\n" ); document.write( "The lengths Ann swims at session $\"+n+\"$ is:
\n" ); document.write( " $\"+10+%2B+2%2A%28+n-1+%29+=+50+\"$
\n" ); document.write( " $\"+10+%2B+2n+-+2+=+50+\"$
\n" ); document.write( " $\"+2n+=+42+\"$
\n" ); document.write( " $\"+n+=+21+\"$
\n" ); document.write( "After 21 sessions, Ann swims 50 lengths
\n" ); document.write( "for the 1st time\r
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