23. Eric and Eleanor are training on a 720 metre circular track. They run in opposite directions, each at a constant speed. Eric takes four minutes to complete the full circuit and Eleanor takes five minutes. How far does Eleanor run between consecutive meetings of the two runners?
A $355 \mathrm{~m}$
B $350 \mathrm{~m}$
C $340 \mathrm{~m}$
D $330 \mathrm{~m}$
E $320 \mathrm{~m}$
23. E The ratio of the times taken to complete a circuit by Eric and Eleanor is $4: 5$. Therefore, since distance $=$ speed $\times$ time and they both complete the same circuit, the ratio of their speeds is 5:4. Hence, since the total distance Eric and Eleanor cover between consecutive meetings is a complete circuit, Eleanor will run $\frac{4}{4+5}$ of a circuit between each meeting. Therefore Eleanor will run $\frac{4}{9}$ of $720 \mathrm{~m}$ which is $320 \mathrm{~m}$ between each meeting.