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QUESTION 20 An radioactive material decays exponetially at a rate of 6.8% per week. How much material will be lest after 1 year, if the initial amount was 40,000 kg. Include the equation of the model. TT TT Paragraph Arial 3 (12pt) T %DOQ T' TE 'S "T ft Mashups T" HTML CSS - Path: P Words: 0 QUESTION 21 A bacterial culture grows exponentiall at a rate of 6.4% per hour. If the culture present total is at 250,000 cultures. What was the initial amount 10 hours ago Write the equation for the amount of cultures using the initial amount. TTTT Paragraph Arial 3 (12pt) E T- | 0 0 Q ==== = T'T 4 - - Click Save and submit to save and submit. Click Save All Answers to save all answers. Save All Answer arch

plz do 20th question as soon as possible by showing all formulas

Answer 1

any O Let 'n be the main of radioactive material at time t. dm The Epiration of yadio active decay is =-um dt Where Mis a constant dm (variables are separated gutegrating both sides) dm - udt S d = -J udt te' -ut c' ma ee - ut + c =) In m = (2 m- cent is the Equation of the Model At t-o (initially) m= 40000 we get Put t=0, m= 40000 in ② 7410) 40,000 = ce 40,000 ا اءمے Ce Now weget at t= 1 (week), ma 6.8% of 40,000 Put t-, me 6'8 x 40,000, C=40,000 in M(1) 6.8 x40,000 = 40,000 x e loo 100 =) é M 6.0 Тоо M=-In ( 6-8 Too 2.69 now put t= M= 2.69, 52 weeks (lyear) in Equation ③ , ③, weget C-40000 -269 (52) 4,000 x 2 m m -57 7.13 X 10 - (approximately)